The Edwards 7633 series Dome Stations are used to visually and audibly indicate the placement of calls from a connected pull station. Stations are available with 2 or 4 lamps, the domes are designed with barriers between the lamps to prevent visual interference of signals. The 7633 mounts in a standard double gang box with a plaster cover and a minimum depth of 1-3/4 in. Boxes and plaster covers not supplied.