HARKILA Base Warm Half Zip Neck - Mens - Willow Green / Shadow BrownHARKILA Base Warm Half Zip Neck Mens Willow Green Shadow Brown The Harkila Base Warm undershirt is composed of a blend of 60% wool, 20% polyester and 20% acrylic. This makes it more hardwearing than a pure wool garment, and it will give you many years of wear. There is a terry finish inside for extra warmth, and flat seams for comfort when worn under your other hunting clothes. It features a high neck with a zip, to give you extra protection from the