I promised that I would write a comparison of these dual pouch boxer briefs. To be a little fair, SHEATH 4.0 does have a SHEATH V collection aimed for Sports. In some ways you can say that it’s not a like-for-like comparison. However, the pouch system doesn’t really change in the design.
You may want to read our review on the Separatec underwear and the Sheath underwear before reading this comparison.  Or you can read it after reading this too.  I will also post the links on the bottom of the review.
Before we start the comparison, I would like to provide some information on material between the SHEATH 4.0 regular and the SHEATH V collection so we get a sense of the difference.


  77% Polyamide

  23% Spandex

  6.5″ inseam


  92% Modal

  8% Elastane

  3.5″ inseam


  92% Modal

  8% Elastane

  6.0″ inseam

From the chart above, you can see that the only difference between the SHEATH 4.0 and the SHEATH V is the length of the inseam.  Both SHEATH boxers have the same sports waistband; so comparing the SHEATH 4.0 and Separatec shouldn’t still be fair.



Separatec has specialized in men’s underwear since 2010 with a goal to make better underwear which could perfectly fit men’s reproductive structure. With that in mind,  they got the idea of designing underwear with two pouches. The support pouch can provide independent lift for the men’s scrotum, and the front pouch can give enough space for the men’s penis. It took 8 years of continuous updating and improvements to get to their final product.  


During the Iraq war in 2008, Army Sergeant Robert Patton had a vision for a new design of underwear that would eliminate irritation resulting from the sticking of balls and the inner thigh under extreme circumstances. After he had the idea, he made some garments for himself.  After he was discharged from the Army in 2013, he worked with a professional tailor from Vietnam and launched a Kickstarter and crowdfunded the SHEATH 2.0.  Over the years, there have been changes to try to continue to improve its design with the same goal in mind.
Both companies started around the early 2010 and took time and effort to iterate their designs and make improvements.  I’ve read on a lot of social media comments saying the underwear is designed by women for men and don’t think that the design is thought through. If I were the designers, I would totally feel offended by these comments. Men’s underwear has not changed much over the years and I think these are quite innovative. 
I’ve reviewed many pouch underwear – underwear that has a larger pouch area to support your package, to the Hook/BN3TH/2UNDR type which has a U shape pouch and to the SAXX’s V shape pouch. These are all underwear to help support your package during active activities and also avoid your thighs from rubbing directly.  So this dual pouch takes it to another step. It separates your penis with your scrotum.  Both designs took different approaches where we will compare next. 

Pouch Design:

Both brands took a different approach in designing the dual pouch. Both pouches are very different: the SHEATH has a D shaped pouch having the flat side facing up for your sack and hole for your penis to go through to a pouch with a regular vertical fly.  The vertical fly is much simpler to use and to put on.  I guess it’s because we are used to this type of fly from other underwear.  One down side of this design is that if you break a boner or you have a greater length, you may be exposing yourself without knowing it.  I was brushing my teeth after showering and noticed that parts of my penis were exposed through the mirror.  This may not be a problem because there is not a lot of place you would just be wearing your underwear.  It’s most likely your bathroom, your house and the change room at the gym.

Separatec creates a pouch with less fabric. The sack pouch is created by stitching two pieces of fabric creating the contour pouch just under the hole where your penis goes through. The penis pouch is where the Separatec is very different. The penis pouch has dual purpose –  it’s a pouch for your penis to “sit” on and a fly for you to flap up to urinate.   The exterior measurement of this medium size boxer is about 6 7/8 inches from the waistband and the fold is about 2 1/2 inches.  The reason why I put quotes in the word “sit” is because you need to have enough length for the head of your penis to sit on the flap.  Since I have a much shorter penis at flaccid, I have to push the pouch fabric up so that it would sit on the pouch.  You can see what I mean with the photo above where I was wearing the green Separatec.  Taking photos is not as easy and takes a lot of time, since you are fiddling around with your guy may cause it to semi-erect.


  • Width of Pouch: (see photo (a))
    • ~5 inches (Sheath)
    • ~4 inches (Separatec) 
  • Height of Pouch: (see photo (b))
    • ~5.5 inches (Sheath)
    • ~6.5 inches (Separatec)  
  • Sack Pouch starts from waistband:
    • ~2.75 inches (when pull straight) (photo e) / ~4.5 inches (lowest point without any pull) (photo d) (Sheath)
    • ~5.75 inches (photo c) (Separatec)



I’ve read a lot of comments from Facebook saying that the hole is not BIG enough for their penis to go through.  I know some guys are just saying it thinking that he has a big twig and these won’t work.  There are also comments saying that these underwear are designed by women who don’t know much about men’s private parts and/or design by men who have small penises.  
I measured both holes, and I believe the size of both are identical.  It is hard to measure the height and width of the hole, so only use this as reference.  The Separatec measured 1.5 inches by 2.0 inches with a girth circumference of approx. 6 inches.  The Sheath measured 1.875 inches by 1.875 inches with a girth circumference of approx. 6 inches too.Again, the circular hole can stretch multiple ways so the measurements could be different.  The circumference of approx 6 inches would be the better measurement to use.  Just searching online to get the most updated information on surveys of girth size and found that the average flaccid circumference is 3.66 inches and erect circumference is 4.59 inches and the 6 inches in the design is definitely enough for the average man.  
So definitely I do not see any issues with the design of the hole.


Both flies are completely different.  I already mentioned about the fly when talking about the pouch, but I believe it makes sense to talk about it a little more.  The Sheath design is the traditional vertical fly and most men have owned underwear with this type of fly.  The only difference is when you open the fly, your penis is already there – there is no need to dig into the fly and pull your penis out.  The traditional fly has fabric to cover your penis and act as the dual layer fabric to create the snug fit of your package and hold it in place. 
Separatec uses a different approach with the fly.  The external pouch needs to pull down and flap up to open the fly.  The reason why I say that you need to pull it down because the flap wraps around your head of the penis.  You don’t need to pull the flap down, but push our penis out of the flap and open the flap by going up.  The flap is only single layered, so there is less fabric to protect your penis and allows it to hang around a little bit more.  
The SHEATH fly feels more supportive overall; however, from a side view you could possibly expose yourself.  If you have read my review, you would have seen the boner photo and how I have exposed my penis when having an erection .  The Separatec fly is unique and I think there is room for improvement.  It fully hides your penis even when you were having an unexpected erection.  However, the Separatec fly is not as easily accessible.  If you are wearing jeans, you have to unzip the jeans, dig down to the flap and adjust and pull the flap up before you can pull your penis out.  The Sheath is much easier as you unzip your jeans, you just need to reach into the side fly and your penis is already there.
One thing to note, after you have done your business, you would need to put your penis back into the pouch.  The Sheath still felt a bit odd as you need to make sure it fits totally in the fly before zipping up – you don’t want to hurt your penis.  The Separatec requires you to pull down the flap to cover your penis.  
This may not be for everybody, but make sure you shake off as much as possible after going.  Both dual pouch underwear only have 1 layer of fabric to absorb anything you have not shaken off.  I know it’s a bit gross, but we all men know what happens after you pee.  The thin fabric on the Separatec may not be able to absorb what you haven’t shaken off and may then get some of it on your jeans/pants.


The fabric of the two pieces are very different.  Separatec uses Polyamide and Spandex; whereas, Sheath uses Modal and Elastane.  I understand that Separatec also has a different collection that uses Modal; however, they use Spandex over Elastane in those collections.

Polyamide – which is a better name than Nylon.  Polyamide has a long history and is the first synthetic fiber developed. Polyamide fibers are made of several molecules linked together creating a long chain.   The fabric is not very insulating, which makes it a good fabric for underwear, since we do not want heat to build up.  When this fabric gets wet, it will remain to be wet for some time, but it does come will a cooler feeling.  Polyamide was originally made as an alternative to silk which is soft and flexible which makes it a perfect piece of fabric for your crown jewels to sit in.

Spandex – which is also known by the brand name Lycra which allows stretch in many pieces of clothing.  The synthetic fabric can expand to nearly 600 percent of its size and does not restrict the range of motion, and then snaps back in place. Spandex is also breathable, wicks moisture, and dries quickly

Modal – Is a fabric that is extremely hard-wearing and keeps its shape and finish, even after frequent washing. It has a silky texture feeling.  One key feature of modal is that it does not trap perspiration and odors, so your underwear won’t smell as made as synthetic fabrics.  Also modal fabric is 50% more absorbent than cotton which is also better than cotton. 

Elastane – is actually the same fabric like spandex. It’s just a terminology that is used in different regions.

The fabric of the Separatec boxers feels much thinner than the Sheath ones.  Based on the fabric information above, you can see that the Separatec will stretch a lot more than the Sheath ones with it’s high percentage of spandex/elastane.  The only difference is the main material of Polyamide/Nylon and Modal.  Both fabrics are very soft, but the Separatec is a little smoother to touch.  Sheath feels more like regular underwear than the Separatec since the Separatec feels very thin.  Because of the thin material and the silky properties, the underwear shows your package a lot more.  The Separatec does give you the feeling that you are not wearing anything, but the Steath is not that far behind.


Both waistbands are considered sports waistband which is sewed onto the underwear.  Both are present their logos with some design.  You can see that both waistbands have the same width.  One difference is how the waistband is sewed together.  You can see the Sheath is stitched together in one place; whereas the Separatec overlaps and are stitched in two different places.  Not sure why it was done that way.


From the photos above, you can see that the Sheath boxers is a little wider than the Separatec and the Separatec is longer than the Sheath.  The Separatec has more spandex than the Sheath, so they are more stretchy overall.  I stretch both boxers together in the waistband, and the Separatec stretches about 1-2 cm wider than Sheath.  

See below on the sizing chart of the two boxers:

You can see that SHEATH offer larger sizes and Separatec only offers up to 42 inches.

For my experience if you fall in between the sizes, you may opt for the smaller size with the Separatec if you want them to fit better.  For Sheath, staying with the size would be optimal.  This is based on my experience – you really need to see how things work for you.  The biggest concern wouldn’t be your waist size, but the fitting of your penis and sack would matter more.


Both boxer briefs have a different dual pouch technology.  For myself, the Sheath dual pouch seems to work better than the Separatec.  I am a grower and have an average size flaccid penis.  I find myself falling out of the Separatec a lot more than on the Sheath.  One problem I see with both dual pouch technology is when you are a show-er.  Anything penis at flaccid over 6 inches may have problems.  When I wear the Sheath, there is about 1 inch room before I hit the bottom of the fly.  So anybody under 6 inches at flaccid should be able to point down without having to wrap or point into different directions.  The Separatec has a lot of fabric for larger flaccid penises.  I spoke with someone on Facebook and he said that he was about 6 inches and he felt that the Separatec was uncomfortable.  He had to start wrapping his penis a bit because the fabric was stretching if he just pointed down.

The Sheath has a button feeling to support your penis and it feels more of a tighter support which could be the reason why it falls out less than Separatec.  The Separatec pouch is much looser and does give you the feeling that you are wearing nothing.  Unfortunately, with no feeling, the penis can easily fall back into the hole more often.

The Sack pouch implementation is different too.  I actually like the Separatec pouch more, but if you have a larger sack or a swollen sack, it may not be big enough for your sack to sit on.  My sack fits very well in the Separatec sack and it’s very supportive.  Even when certain movements the lift of the sack feels much smoother and less odd.  The Sheath sack really needs to get used to since it relies on the fabric to fit right behind your sack, so that your sack can sit into the pouch.  But the pouch is sooo big that my sack doesn’t even fit into the pouch.  It just hangs in mid air and what it is supporting is the perineal area right behind my sack.  It does cause some odd lift feelings before you get used to it.  

Overall, I still have mixed reactions to both brands and both technologies.  I would say the SHEATH works better for me, but I do like the fabric of the Separatec.  There are pros and cons on both brands and I hope my comparison would help you decide on which one to buy.

Please leave feedback on what else you want to see in the future, or if I have missed anything.  As always please like my Facebook page, or Instagram.  If you haven’t filled in the survey, please do so too!



After wearing the both SHEATH 4.0 and Separatec Dual Pouch systems for the 3+ times,  I wanted to provide some afterthoughts.  The Separatec does give you much more freedom in the feeling side and does give you the wear nothing feeling once you put them on.  However, once your penis falls out of the hole, you will start to readjust or give it up and use it as a single pouch.

The SHEATH does give you the initial lifting feel, but that feeling quickly goes away.  However, my sack does fall out of the pouch when I sit around, but my penis continues to stay through the hole.

I also spoke to guys on the Separatec posts on Facebook, and there are complaints that the Separatec sack is not large enough to fit their balls onto.  I have no trouble with my sack fitting into the pouch, but someone also said that our sack was designed to be hanging and not wrapped in  the  Separatec pouch.  That could be one reason why our penis will fall out of the hole on the Separatec.  I don’t know if that is the reason, and have no scientific proof that the pouch is the reason why your penis will fall out.

I’ve seen very positive feedback on the Separatec and also see true followers for the SHEATH.  I guess there is no difference between car manufacturers like Honda vs Toyota or BMW vs Mercedes.  They both do the same thing, but have different implementations to get the car moving.  Both brands have different designs, but also support your penis and sack with their dual pouch technology.  I really love new technology in men’s underwear since we all deserve something better for our little guys down there.  

Both are great underwear when it works for you.  From all the reading and myself personally testing both systems, I would say that my guy profile fits better with the SHEATH.  As noted before, I really love the Separatec materials, but the SHEATH keeps my package supported and there is less fallout from the penis pouch.  I believe  guys with larger penis lengths up to 6ish inches will love the Separatec over the SHEATH.  

The SHEATH are not cheap and they are about 2x the price of a pair of Separatec.  I really hope that Separatec will offer their underwear in single packs and provide free first time shipping, so that guys can try them out before committing to buy 3 or 7 pairs.  I believe most men like me will put underwear that doesn’t work aside and don’t touch them until it sits there long enough before going into  the garbage bag.  Men don’t share underwear and don’t give them away to others with them knowing that you have worn them before.  Buying a 7 pair and them not working is a waste of resources.  I hope one day Separatec will sell their products in  trial packs so that guys can try them at a lower price and if they work, they will buy more.  If they believe in their products, they should do this and not sell 3 or 7 pairs at a premium price and not get business from them.  As for SHEATH, if they offer a discount code to have a premium pair of underwear with free shipping, I think more men will buy more from them once they know they work from them.

I personally will not buy more from Separatec and SHEATH, as I need to buy different types and brands so that I can provide my honest views to you.

Your Views

If you own a pair, provide your review below – just one click! If you have any questions/comments, you can anonymously leave your feedback below.

You can also upload your photo wearing this piece of clothing. Please make sure you do not show male anatomy or else it will be deleted. If you want to show off your pairs, you can reach us and we can put it as part of the 18+ section. Thank you!

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So, I am 61 years young 6’2” 220 lbs 39 waist. I am a grower not a shower. I have always worn Hanes Comfort Stretch Tagless Briefs in an XL. They have been ok but smash everything together. I tried the Sheath briefs and the pouch for the boys was very uncomfortable and the place for the rod just smashed it not comfortable very big on the fit.

I saw these Separatec Briefs in an online add, and finally after much debate thought I would give the 7 Pack Cotton Stretch Briefs a try. After reading several reviews I decided to order the XL. They were a little big and did not hold the rod in the hole, kept popping out. I returned them with out any problems and ordered them in a Large. Still just slightly loose, I washed them in warm and dried them, now the fit is amazing, so super soft and a very nice elasticity to them. These I would say are a midrise, however they sit just slightly above the hip bone. My rod stays put even with bending, squatting and sitting.

As far as I can tell the fit is very important, now the hole for the rod sits flush against the base of the rod at my pelvis, and is so very comfortable and soft. Your boys feel like they are being held gently and away from your thighs. Your rod is also in its own pouch just chilling all day. Not a problem at all as my size changes during the day, if you know what I mean. Mind you it is a slightly snug fit; however, it is very comfortable. I do not even have to do any adjusting at all. Feels like I am not even wearing any underwear at all. The waist band is very soft and does not roll. As the day goes by, and as all men know we change size by temp and mood it is not a problem plenty of room in the front pouch. These are also very good to sleep in.

I can’t say enough about this product. Just pull them up and everything automatically goes into its own place. Everything in its own place no sweat, no sticking just so darn comfortable. The fly is so easy to use, unzip pull the flap up and let your rod out and do your business.

These are the best underwear I have ever owned. I am ordering another 7 Pack of the briefs and a 7 Pack of the trunks for colder weather. I am going to throw all of my other underwear away and it will only be Separatec for me from now on. CUSTOMER FOR LIFE!!!!


I got a couple pairs of Sheath trunks and have been wearing them for a couple days. I like them, but they fit looser than I like. The company was great and is sending a size smaller at no charge. I just ordered a 3 pack of the Separatec. I greatly prefer trunk style to boxer briefs, but I usually like polyamide/spandex better than a cotton or modal. We’ll see how it goes.


I have not tried the mesh sheath. I used to have some mesh CKs. For the past 10 years I’ve been wearing CK trunks made with nylon/elastane (steel, one, micro). I love how they hold up and continue to support. I had a brief period where I went to MeUndies, but they did not maintain their support over several washes. I went back to CKs but more recently have been seeing ads for different single pouch brands. My search for the best option led me to the dual pouch and then to Wearviews. I’m a little nervous that I’m going to fall in love with the dual pouch and will discard all of my trusty CKs. Just two days of the Sheath trunks and I noticed a big let down with my usual trunks. I don’t know how you continue to wear different varieties when you find ones you love!


Enjoy the Separatec primarily for workouts in gym shorts. Rather challenging to access through my fly when using a urinal when worn with pants. One has to dig to get to the end of the sheath to gain access. For me, the penis sheath could be roomier as I am above average in size and find it a little constricting, If offered with a large penis sheath option they would be perfect.

patrick horrocks

Thanks so much for this comparison. I have been wearing Separatec, and David Archer underwear (virtually the same) for over a year now. I like them very much. I agree the the fabric on the penis cover is very thin and doesn’t absorb drips well. My only other issue is that they are somewhat “high waisted”. They seem to fit better and be more comfortable if I fold the waistband over. I have been curious about Sheath. I like the fact that it was developed by a veteran, as I am one as well. I’m curious as to where Sheath is manufactured. The underwear I purchased comes from China which may account for the lower cost. Based on your comparison, I’ve decided to try Sheath. I like the idea that the fly is more user friendly. I have on occasion when wearing jeans with a short rise, had trouble getting “the horse out of the barn”!


Thanks for the update, I really like the fact that you are doing follow ups. There are many times when after a few washes or doing a variety of different activities that I find something I liked out of the package doesn’t hold up for long term use.

Larry Myers

I bought the three pack of briefs from Sepratec. I have never had underwear as comfortable as what these are. I am rather well endowed, and I had been wearing loose boxers for years due to everything being “scrunched” together in regular briefs or tight boxers. I then seen an advertisement for these Sepratec, and thought I’d give them a try. I was pleasantly surprised by the fit. Although the “penis pouch” could stand to be just a touch bigger, things fit very comfortably. I would highly recommend them to all my friends.

Larry Myers

I read the review afterwards


I’m guessing that the pouch in the Separatec for your testicles is not a pouch at all, but the normal resting place for my testicles, and that the hole is for my penis to go into. The mention of 2 pouches confused me. They are extremely comfortable. I’m probably going to order more as I only originally ordered the 3 pack.

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