The TORK A512H 12-Hour Spring-Wound In-Wall Twist Timer is designed to control a variety of indoor appliances and lights. Automate your home or office to save energy and money using the simple twist knob and reliable mechanical timekeeping. Features a time range of 30 minutes to 12 hours, plus it fits into a standard electrical box for in-wall mounting. Designed for indoor loads such as lights, whole house fans, air compressors, water heaters or motors.