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Quantity
1
Description
Our Flex Trunks have been completely upgraded. Built for performance, they feature a custom flex-knit fabric blend that provides full support, breathability, and cool-touch mesh for optimal temperature control.
Reviews
4.6
237 ratings
5
4
3
2
1
Great underwear!
These trunks are extremely comfortable and the sizing is perfect. They stay in place throughout the day.
K
Keith · 3 days ago
Comfortable inside and outside of the gym
Bought a pair recently and it is great to wear in the gym while lifting weights or wearing them under under a pair of jeans when out.
A
Alessandro · June 24, 2026
Flex trunks
Most comfortable , material smooth no drag on other textures , support where needed, like the shorter thigh length . Good patterns
![Storm [inseam - 7"]](https://cdn.shopify.com/s/files/1/1464/5034/files/250304_BiosShort7Storm_0019_98a4f3b9-8ec0-48fa-8353-b49a1a298e93.jpg?v=1778951855&width=256)
![Navy [inseam - 7"]](https://cdn.shopify.com/s/files/1/1464/5034/files/250304_BiosShort7Navy_0019.jpg?v=1773270275&width=256)
![Desert [inseam - 5.5"]](https://cdn.shopify.com/s/files/1/1464/5034/files/250304_BiosShort5.5Desert_001811_f194ef5a-4660-4b49-9569-428cdbe467bc.jpg?v=1773446399&width=256)
