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Flex Trunk

129
Size Guide
Flex Trunk Size Chart

Trunk

Fit Profile: True to Size
Flex Trunk Size Guide
Size: S M L XL XXL
Waist: 28-30" 31-34" 35-39" 40-45" N/A
Leg: 6-7" 7-8" 7-8" 8-10" N/A

 

Your purchase includes our "Love Your Fit" guarantee

If you don't love the fit, send it back and we'll exchange the size so you're happy.

 

Color
Black
Gray
Green
Size

Flex Trunk

Signature 40° Side-Fly • Anti-Odor • Temperature Control • 84% Polyester  16% Spandex


“Lightweight, comfortable, and durable. I can wear the Flex Trunk anywhere with confidence that they will perform!" 




  • You deserve better boxers


      • Cool Where it Counts

    84% Polyester and 16% Spandex, our mesh zones are strategically placed to remove heat and keep you cool when and where it matters most.

      • Side Fly Innovation

    BYLT's signature 40º side-fly offers a more comfortable draw and easier access. It's time you see how we changed men's boxers for the better.

      • No Roll. No Marks.

    The Flex Trunk's no-roll waistband fits comfortably while leaving you mark free after a long day. Say goodbye to boxers that roll and ride up.




    Men's Temperature Control Flex Trunk Underwear Pack by BYLT Basics.



 

Customer Reviews

Based on 129 reviews
5 Star
78% 
100
4 Star
20% 
26
3 Star
2% 
2
2 Star
0% 
0
1 Star
0% 
1
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01/10/2019

Great Purchase

Andrew K.

Bought an Allday-Flex Bundle 4 pack. Tried them on the day they arrived and immediately went online to purchase another 4-pack. The Alldays are super soft. The Flex are more like moisture-wicking sport briefs but still very soft. Both keep you dry all day and are great for either work or working out. The colors are slick too. These are easily the best and most comfortable trunks I've ever owned.

01/04/2019

buy these for your boyfriend

Macie C.

my boyfriend can’t stop thanking me for the bylt all day flex i got him a year ago xmas. i got him a bundle this xmas and he was psyched. we’re 24. so we get psyched about ****** but he tells me all the time he’ll never get another brand bc the opening is very convenient for men.

12/27/2018

Drop cut shirts

Suzanne V.

My bf LOVES the way they fit! He’s 6’5 with an athletic build and these fit him so well! Great material.

12/21/2018

The perfect all-around boxer-brief

Ali W.

My husband bought a pair of these to try and fell in love. Now I’m basically doing laundry for one pair of boxer-briefs. So I bought him two more 3-packs for Christmas so he will have a pair for every day of the week!

12/19/2018

Nothing but amazing!

Tyler W.

Perfect! Love these Alldays!

Flex Trunk Size Chart

Trunk

Fit Profile: True to Size
Flex Trunk Size Guide
Size: S M L XL XXL
Waist: 28-30" 31-34" 35-39" 40-45" N/A
Leg: 6-7" 7-8" 7-8" 8-10" N/A

 

Your purchase includes our "Love Your Fit" guarantee

If you don't love the fit, send it back and we'll exchange the size so you're happy.