This Light Sensor unit Features: 24hrs or light only operation, Selectable spray interval setting of 5,15, 30 minute, Empty can reminder (3,000 sprays), Low battery monitor and operation indicator. With push button design for easy programming. With chemical resistance plastics. Operates on two D-cell Alkaline batteries. Design to fit With almost all-standard metered aerosol cans. One unit recommended for a room area of 6,000 cubic feet. Batteries not included.