Thermalution produce electrically powered heated undersuits that are designed to warm and maintain a diver's core body temperature using Far Infrared Ray (FIR) technology and a flexible non-metallic heating panel. Our Simply Scuba Thermalution products feature an external controller allows for quick and easy temperature adjustment under your wetsuit with a wired controller or drysuit with a wireless controller. The Thermalution waterproof controller<span> sits on a coiled wire with a simple switch to turn the heat on and off and adjust the temperature to three different levels.