Santini Men's Mesh Cycling Base Layer Shirt Size To Fit Chest: M - (37.8 - 39.4") L/XL - (39.4 - 40.9") Short Sleeve Base Layer In Polypropylene Nilit Innergy Mesh High Comfort Seamless Design With Polypropylene Anallergic Yarn Reflects Thermo Energy Generated By The Body Back Into Skin Tissues To Enhance Performance Lightweight And Soft It Fits Like A Second Skin