Columbia Tianium Knit Half Zip Womens 100% polyester Fabric Type: Jersey--A stretchy (plain) knitted fabric, without a distinct rib, used widely for T-shirts Performance Technology: Columbia Omni-Dry--Incorporates a moisture management process where perspiration is efficiently drawn to the fabric surface where it can quickly evaporate. Anti-Microbial--Anti-microbial treatments provide permanent odor protection by inhibiting the growth of bacteria and mildew in the fabric. UV Protection--Fabric is treated to block UV (ultraviolet) radiation from the sun, helping to prevent sunburn. Fabric Content: 100% polyester jersey knit