Heat Holders Original Socks Denim. The Heat Holders Original Socks are the ultimate thermal socks with a Tog rating of 2.34 that is guaranteed to keep feet warm this winter. The Heat Holders Original Sock is a mid length sock that offers a gently elasticated cuff and a normal seamed toe for maximum comfort. The Original Socks features an intensely brushed long pile inside that is incredibly soft, helps to hold warm air against the skin for longer and helps to support and protect feet.