XILI Men's Brief,2-Pack 95% bamboo Comfortable 95% Bamboo Fiber,5% Spandex Opaque area used bamboo fiber material, mesh area used ice fiber material. Mesh design, ice and bamboo fiber are all cool in hot summer Bamboo fiber has particular and natural functions of anti-bacteria and deodorization It is validated by Japan Textile Inspection Association that, even after fifty times of washing, bamboo fiber fabric still possesses excellent function of anti-bacteria