Though officially designated as "a shirt designed to be worn as a sleeping garment in bivouac areas," this versatile Long-sleeve Sleep Shirt can also be worn effectively as a base layer for cold weather activities. 100% cotton construction in herringbone weave wards off chills, so you'll sleep soundly throughout the night. 100% cotton in a herringbone weave Easy slip-on style Front chest pocket with small loop for hanging pens Elastic wrists