This handy light sensor provides extra security when you're away from home. Just screw into any standard light socket. A built-in photocell turns the lamp on at dusk and off at dawn. Not for use with fluorescent lights, appliances or other non-incandescent lights. Use with 25 to 150 watt incandescent lights. Maximunm 150 watt facing up or down in open fixtures. Maximum 60 watt in enclosed fixtures incandescent/halogen. White finish. 2 1/2" high. 1 1/2" wide. For use with incandescent lights only. Rated for 25 to 150 watt bulbs only.