99extra Underwear, 4 Colors Men's Bamboo Fiber Anti-microbial Slim Fit Boxer Briefs 95% Bamboo Fiber/5% Spandex 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 Slim fit size, usual small 2 size to standard size, please refer our waist list description International EMS delivery, U.S. domestic 7 to 15 days reached, other countrys 10 to 25 days reached.