99extra Underwear, Men's Bamboo Fiber Antimicrobial Skinny Boxer Briefs 95% Bamboo Fiber/5% Spandex Imported 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 Use new technology, make this underwear to be thinner and lighter than normal cotton underwear According to authoritative testing figures, apparels made from bamboo fibers are 1-2 degrees lower than normal apparels in hot summer. Apparel made from bamboo fiber is crowned as Air Conditioning Dress. We know, lower temperature is benefit for male genital organ health. Silk covered edge,flexible is less than rubber band,suggest select larger one size for stonger waist or legs Doctor advised a underwear don't use more than 6 months because it will become very dirty although you repeated wash it