Injection molded ABS for durability and corrosion resistance. Additional splash guard for installations subject to light spray and water. 3-Way switch allows both automatic and manual switching. A red LED light activates in Manual mode, a green LED light activates in Automatic mode. Backlighting for easy night operation. Includes a UL listed 20 amp circuit breaker to reset the system. Size 2-3/16" x 3"