These JINSHI boxer briefs are made of bamboo fibres which is superior to cotton. Smooth, lighter in weight, and easy to care for(washer/dryer, no wrinkles, durable). Japanese scientists have found that bacteria which on the bamboo fiber products will be killed about 75% after 24 hours. Bamboo fabric has insulating properties, helping the wearer stay warmer in winter and cooler in summer. It also ensures human and eco health-bamboo plant is organically sustainable, grows naturally without chemicals.