"Powered by seamless technology, this cozy, sweat-wicking layer was designed to be worn under your raincoat on wet commutes or under your ski jacket when hitting the slopes. Seamless construction minimizes chafing Fabric is sweat-wicking and four-way stretch Features Designed for: Training Thumbholes: Thumbholes help keep your sleeves down for easy layering Zipper garage: Helps protect your chin from uncomfortable chafe Fit: Slim fit, waist length."