OccuNomix Hot Rods Winter Liner and Heat Packs Head Liner: Give winter a warm welcome with Hot Rods wind-resistant, waterproof head liner. Made of poly/cotton outer shell with soft fleece lining on the inside. Sewn-in pockets are positioned to cover the ears, and it comes with two regular Hot Rods Heat Packs to insert into each pocket, if desired. Equipped with 3 suspension tabs for securing to safety hat. Hot Rods Heat Packs can be used as hand and body warmers; simply activate and insert into pockets, gloves, mittens or socks. Heat packs last up to 11 hours once activated. Available in two sizes; standard, 2" x 3" and large, 4" x 6".