Made for your most dynamic aerobic activity, whether it be hiking or running, this technical shirt beats the heat with Columbia's sweat-activated cooling technology. Features: Omni-Freeze ZERO™ sweat-activated super cooling lowers the temperature of the fabric when you sweat Omni-Wick™ moisture wicking technology keeps you dry and comfortable Comfort stretch for freedom of movement Incorporates an antimicrobial treatment intended to protect the product from bacterial growth. The active biocidal substance is: pyrithione zinc Centre back length: 28" True to size. We recommend purchasing your usual size Active fit: Body skimming fit with end-use mobility in mind Materials: 100% polyester ZERO interlock Columbia Men's Zero Rules S/S Shirt