ColdPruf Women's Enthusiast Base Layer Long Sleeve Base Layer Shirt - The ENTHUSIAST is a single layer garment made of 100% Polypropylene. This design will give you a close, comfortable fit without restriction. The ENTHUSIAST is lightweight and has been designed to give thermal protection in cold to very cold weather with medium to high activity. Single Layer Flat Seamed Wicks & Evaporates Moisture Style: 57A