HEAT HOLDERS - Women's Thermal Fleece Cable Knit Winter Hat 3.4 Tog - One Size Outer: 53% Polyester 47% Acrylic, Lining: 100% Polyester Machine Washable Ladies Heat Holders 3.4 tog rating thermal winter knit hat. Heat Holders Yarn  Specially developed thermal yarn provides high performance insulation against cold with superior moisture breathing abilities. 3.4 Tog rating  the tog rating is a measurement for the thermal ability of a garment. 3.4 tog is considered to have very high thermal ability. Heat weaving lining  HeatWeaver insulation is a plush fur-like thermal lining that maximises the amount of warm air held close to the skin. Heat Holders - Best seller since 2010, providing a wide range of winter thermal products that we provide in the sock snob online amazon store