Berghaus Men's Vapour Base Crew Short Sleeve 100% Polyester Imported Permanent odor resistance through the use of Polygiene odor free Technology A new open knit structure creates a Highly breathable, lightweight and efficient main body and the Underarm mesh is placed in high perspiration areas Permanent UPF of 30+ (excluding mesh underarms) Permanent moisture management through the use of a denier gradient structure Stretch panels over the shoulder give unrestricted movement