The men’s Waffle Knit Thermal Crew by Filson helps traps a layer of air between you and the fabric – enhancing breathability and overall insulation – making this top the perfect layer. It’s made from heavyweight Peruvian cotton, which has a soft feel that’s comfortable to wear under your sweatshirt or jacket. Rib-knit cuffs stay in place. The bar-tack reinforced side-seam slit gives a little extra mobility.