Alleviate aches and pain with this iTENS electrotherapy device kit. Enabled for smartphone use and FTC approved, this device pairs with your iPhone or Android via Bluetooth, which eliminates the need for wires and controlling devices. The laser printed silver paint used as the conductive median delivers an ultra-smooth sensation of current. User only needs to replace the high quality hydro-gel pads and not the wing/electrode. The smart phone app allows for up to 9 devices to be wirelessly controlled at once. The lithium ion battery provides up to 24 hours of continous use on a single charge, and it recharges in less than 2.5 hours. USB charger included Electrode color-Green Color: White.