Men's Bamboo Fiber Health Slim-Fit Cross Striation Boxer Briefs 95% Bamboo Fiber/ 5% Spandex Slim fit size, usual small 2 size to standard size, please refer our waist list description Bamboo fiber contains an antibacterial substances called "Bamboo-Kun", it will inhibit the growth of bacteria, prevent mites, deodorant, Japanese scientists have found that bacteria which on the bamboo fiber products will be killed about 75% after 24 hours Maybe you don't know Bamboo Fiber before, but it is more soft, breathable, flexible than cotton. It's worth to try. Doctors recommenda pair of underwear do not use more than 6 months, even though you repeat washing, but it will still be very dirty Free return and replacement for size problem.