The Occunomix winters liners improve your employee's performance and comfort when working in cold temperatures. There are four unique features available only in Hot Rods winter liners. Each model, with the exception of the WL3 series, is manufactured with a short elastic strip in the forehead area to keep the liner snug against the face and cold air out. A DuPont Thermotex Wind Barrier provides additional ear protection from cold wind. A strip of 3M reflective film has been placed on the back of neck for extra safety. The best feature is the two built-in pockets, approximate to the wearer's ears. Each pocket holds a Hot Rods warming pack. When the packs have been activated, an oxidation process takes place, which causes a safe, natural reaction releasing heat for 7-11 hours. This will keep the wearer's ears toasty warm. Warming packs sold separately. The two layer WL5 model is 100% cotton twill with DuPont Sherpa lining. Shoulder length for added cold protection. The cotton twill and binding are flame retardant until washed. Fasteners are flame resistant. The white Sherpa is not flame resistant. Navy color. 3/package. 36/case. Sold by the each.