The Pro Flex is engineered to move with minimal friction and complete comfort. These Boxer Briefs feature The Original 3D Pouch to ensure everything is separated and supported, so you can always put your best foot forward.
The fabric is a breathable, moisture-wicking polyester blend mesh featuring Ionic+® anti-odor technology that does not wash out.
Fabric: 89% Recycled Polyester, 11% Spandex
Free standard shipping is available on all orders above $75 (after discounts and before taxes).
All available shipping options will be visible at checkout. We ship orders within 1-2 business days, but this can increase during promotional periods.
We offer a 30-day return window for all purchases made directly through our website. To submit a return request, please use our online portal: returns.bn3th.com.
For more information, check out our Frequently Asked Questions page.
ENGINEERED COMFORT
Overall rating: 4.7352114 / 5 from 355 reviews.
The Pro Flex Boxer Brief offers exceptional comfort and support, with a snug and breathable design. Customers appreciate its quality and fit, though some have mixed feelings about the fabric. The anti-odor technology and recycled materials add to its appeal.
Review topics: ["size","fit","fabric","support","length","color","material","issues","style","design","weight","pocket","feel","look","weather","legs","quality","comfort","customer service","wear","boys","underwear","boxer briefs","pouch","trunks","pair","brand","boxers","briefs","waistband"].
"These are excellent boxer briefs. I like the feel of the fabric, the stretch and moisture wicking properties, and how they stay in place and don't ride up. I also like the pouch design which is supportive and comfortable. I especially like these for working out at the gym but also use them for daily wear. I was so impressed with the first ones I purchased that I have bought four more."
"On 5/28/2026, I ordered the then-new Pro Flex Boxer Brief in 3 colors. I was pleased to see that the exceptional build quality that I have come to expect from BN3TH is clearly evident. And the "breathable, moisture-wicking polyester mesh with Ionic+ anti-odor technology" seems to work very well here in the hot summer of Phoenix, Arizona, so I ordered 3 more. The bottom line is that I like it very much. However, I must say that for the winter half of the year, I prefer the somewhat thicker material (which is not mesh) of BN3TH’s Infinite Boxer Brief with "lonic No Stink" technology, which has sadly been discontinued."
"Thank you"
"None"
"Super comfy and fit great"
"I have worn BN3TH underwear for a few years now and as much as you can like a pair of underwear these are great. The support and comfort they provide is not really comparable to any other brand out there. I tried several different brands and the twig and berry comfort of the BN3TH is the best. No weird separator or fabric to rub you in the wrong places. Just a nice soft pouch for the boys to sit. I recommend them to any guy looking to get support and comfort all in one comfortable package."
"My husband has gone on and on about these. This specific type is perfect for work! (Compared to the “icon” ones that are made of Tencel—which are more for everyday leisurely wear in his opinion). These are very durable and still very soft. They hold everything in place perfectly, as well ( —according to him). Anyway, we definitely recommend them lol. Please make some for females! Loungewear/ pajamas/loose fitting clothing - in the tencel material- would be amazingggg! Side note: My husband is roughly 225lbs, 5,10”-5,11”ish, wears a size 38 in most pants/ shorts, or XL in shorts not sized in numbers. He has ordered & bought probably 10+ pair of these, possibly more, and only ever bought size XL - and there always fit perfectly no matter which types he gets - so they are definitely true to size, for sure! (He always wears the boxer briefs). Hope this helps!:)"
"My husband has gone on and on about these. This specific type is perfect for work! (Compared to the “icon” ones that are made of fencel—which are more for everyday leisurely wear in his opinion). These are very durable and still very soft. They hold everything in place perfectly, as well ( —according to him). Anyway, we definitely recommend them lol. Please make some for females! Loungewear/ pajamas/loose fitting clothing - in the tencel material- would be amazingggg! Side note: My husband is roughly 225lbs, 5,10”-5,11”ish, wears a size 38 in most pants/ shorts, or XL in shorts not sized in numbers. He has ordered & bought probably 10+ pair of these, possibly more, and only ever bought size XL - and there always fit perfectly no matter which types he gets - so they are definitely true to size, for sure! (He always wears the boxer briefs). Hope this helps!:)"
"Super comfortable and keeps things cool which is awesome"
"Love them. Very comfortable"