Keep feet warm on the coldest of days and pull on this pair of solid colour crew length Heat Holders for men, the warmest thermal sock.Thick, chunky and with a massive tog rating of 2.34, Heat Holders are made from a specially developed heavy bulk yarn which has extreme thermal qualities. With long pile cushioning, these thermal socks will help keep feet fully comfortable and supported.he inside of each sock has been intensively brushed that not only feels sensationally soft but also traps warm air close to the skin keeping your feet warmer for longer. Features: 2.3 Tog Thermal Yarn Thermal Brushing Thermal Loop Specifications: Colour: Black Material: 91% Acrylic, 5% Nylon, 3% Polyester, 1% Elastane Model Number: BSMHH04H1BLK21 Self Assembly Required: Yes