Check the listing for details. Zerofit Knee High Length Socks - Black. Condition: New with tags. Listed at 35.66 USD. Both sock options have been engineered using the same Heat Threads that exist in the award-winning Zerofit Heatrub Ultimate baselayer which has been independently tested and proven to be five times warmer than a standard baselayer. These Heat Threads on the inside of the garment generate warmth instantly and offer an incredibly cosy and snug feeling of heating happiness! Following extensive feedback from existing customers, the new Knee Length Heatrub Ultimate Socks have been created to be easier to slip into motorcycling, hiking and skiing boots, as well as golf shoes. To achieve this, the Nano Pods that exist on the sole of the Standard Length Heatrub Ultimate Socks have been removed, while the length of the new socks has also been increased significantly from 27cm to 35cm to offer more.