Heat Holders Rib Turn Over Sleep Socks Our advanced Japanese designed thermal yarn provides performance insulation with superior moisture breathing abilities and softness. Our innovative knitting technology produces our UK PATENTED long looped cushion pile to hold more warm air, increasing the TOG rating. Our expert brushing process maximises the amount of wram air held inside each sock for unbeatable warmth and all-day comfort. Material Content: 92% ACRYLIC 4% NYLON 3% POLYESTER 1% ELASTANE Washing Instructions: Machine Washable