Like all Carhartt thermal underwear, we've designed this new midweight cotton crew neck top for comfort, warmth and durability. Made of premium, 9.5-ounce, 100% cotton, it features rib-knit neck and sleeve openings that keep warm air locked in. The fabric, which is 30% heavier than most other cotton thermals, also traps body heat in for warmth. All seams are flat-locked for added durability, comfort and strength, and its low shrinkage provides a consistent fit. For function, ruggedness and ease of movement, this job-tested crew neck has it all.