There ain't no rest for the wicking--we'd call on these undies 8 days a week if we could. The best undies are ones that feel barely there, comfortable enough to sleep in, sleek enough to work in, wicking enough to sweat in. The What the Sweat are just that. These undies are designed to breathe and wick but most importantly stay put all day! Poly/nylon/spandex. XS(2), S(4-6), M(8-10), L(12-14), XL(16).