These are the socks with an integrated electrotherapy system that delivers pain relief to the feet. Using Transcutaneous Electrical Nerve Stimulation (TENS), the controller connects to the socks via snap-on fasteners and sends harmlessblock pain signals electrical pulses to the feet that stimulate the nerves and block pain signals to the brain. Its offers five different modes and three intensity levels to provide customized relief and displays the settings on a large LCD screen. Hand wash, air dry. Includes left and right socks, electrode wires, gel pads, and four AAA batteries. Not for use by those with pacemakers. One size fits most.