The Nike Hyperwarm Compression Mock is designed to keep you warm, even when it's not. It uses a brushed polyester Dri-FIT® technical fabric for maximum warmth and to help keep you dry. Compression fit provides support while the mock neck construction and sleeve cuffs help retain heat. Flat-seam construction helps reduce chafing and ergonomic seams are designed for movement. 84% polyester/16% spandex. Imported.