Duofold by Champion Thermals Men's Long-Sleeve Base-Layer Shirt, Navy 60% cotton/40% polyester texture Imported Ideal on its own or as base-layer thermal underwear. Tag-free banded crewneck won't itch or scratch your neck. Non-chafe flat-locked seams feel soft against your skin. Close-to-body fit allows for easy layering. Soft texture-rich knit traps air between two thermal layers. Result: a chill-blocking barrier that keeps you comfortably warm.