These socks by Snow Deer have three heat options (purple for high, white for medium and blue for very low) and rechargeable lithium batteries that can very last as many as 6.5 hours when used on the lowest location. Lab effects also showed that the socks are wonderful at moisture-wicking, https://singles-cruises48146.wssblogs.com/31618155/the-best-side-of-knee-compression-socks