The original workhorse in the Polarmax Collection, Single Layers are your standard, dependable thermals. This Polarmax® Kids Youth Single Layer Crew Neck thermal base layer has single jersey knit with slight brushing for a soft, lived-in feel. This thermal crewneck long-sleeve shirt has MTF polyester fibers, which work to transport moisture away from the skin to keep you warm and dry. This thermal shirt has a straight hem and relaxed fit for everyday comfortable use.