PRODUCT DETAILS How It FitsSlim Fit: eases over the chest and shoulders, easy to layer under shirts and sweaters. Made ForKeeping it cool under sweaters, button-ups, and other layers. This undershirt is made using a super-soft cotton-modal blend with our DropTemp™ Cooling technology. Built In TechDropTemp™ Cooling technology, Flat Out Seams™, Three-D Fit™. Made FromSuper-soft modal (38%), cotton (57%), and elastane (5%). This product is OEKO-TEX STANDARD 100 certified which means it is safe from harmful chemicals. Measurements29" body length, 17" sleeve length for size M.