These socks provide 360° heating for the entire foot, including toes and back. They feature an app for adjusting temperature from 86°F to 158°F and monitoring power levels. They include 7.4V rechargeable batteries, offering 6-8 hours of use under normal conditions. Price drops from $39.99 to just $19.99. Shipping is free with Amazon Prime or is otherwise a flat $6 per order.