Hot Chillys Men's Micro-Elite Chamois Crewneck Lycra,Polyester,Polyester Blend,Spandex Imported Fabric is also lightly sanded on the inside for added softness, comfort and warmth UPF rating of 30+, Warmth Factor = 8 Flat seam construction for seam strength and to eliminate abrasion Bio-Silver antimicrobial yarns to help control odor Drop tail