UPF 50 + BUILT IN, FOR SPORT AND PLAY

About UnderFlex

We aim to be your favorite pair of underwear. UnderFlex compression boxer briefs are made for use in our out of the water, with UPF 50+ sunblock built in. Fitting snug to the body, they'll work under your favorite pair of swim trunks, under a wetsuit, and even under your pants. And they'll look great no matter what.

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