The Intermatic T104-20 In-Wall Water Heater Timer Switch is a wall-mounted timer device designed to control an electric water heater. Often described as a little gray box, it replaces a standard wall switch to automate when the water heater turns on and off. This model carries the part number T104-20 and is intended for in-wall installation to manage a connected electric water heater. It provides automatic, controlled operation of the water heater as part of a home electrical system.
