ColdPruf Men's Enthusiast Base Layer Long Sleeve 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 weather. Single Layer Flat Seamed Drop Tail Hemmed Bottom Wicks & Evaporates Moisture Style: 97-NV