The Mens Mount Tam Sweater 1/4 Zip is a comfortable sweater with simple ribbed details and fleece lined collar. While others shiver the Mount Tam delivers. Comprised of 40% cotton, 40% acrylic, and 20% wool, the Mount Tam is packed with warmth. Its fleece lined collar keeps your neck impervious to the cold and the ribbed cuffs and collar help trap and store body heat as the grey season approaches.