The Heat Holders® Camellia Original Solid Black women’s sock offers the same warmth and comfort as its crew socks with non-slip grippers on the bottom that provide better traction in both indoor wood or tiled surfaces. The slipper sock is not recommended for use in shoes or boots. The warmest thermal sock is thick, chunky and includes a massive tog rating of 2.34. It is made from a specially developed heavy bulk yarn with long pile cushioning. The non-binding, diabetic friendly sock comprises of 91% acrylic, 5% nylon, 3% polyester and 1% elastane.