This winter hard hat liner consists of three liners to keep warm air in and cold air out even in freezing cold temperatures. This liner consists of a 100% cotton twill shell, a 3M Thinsulate middle layer with a heavyweight fleece lining. The outer shell and binding are flame-retardant until washed. Polyester fleece lining and fasteners are flame-resistant. The long neck is designed to protect your neck from cold air and wind. This liner features built-in pockets at the ears to store disposable warming packs for extra warmth during the long, cold winter months.