Ltpgtthe bell led photocell gls bc 9w es is a lightbulb that switches itself on via a photocell sensing light during the day the photocell turns the light on once the sun has gone down meaning you dont have to worry about turning the lights on yourself dual 360 degree sensors detect light form all anglesltbr gtltbr gtperfect for home security or outdoor safety the bell led photocell gls bc 9w es can give the impression of occupancy without the need for timers producing 810