Dusk to dawn light control. Compatible with CFL (compact fluorescent) and LED (light emitting diode) bulbs. Turns bulbson at dusk and off at dawn. Includes removable lens shield to block light reflection, reducing blinking. May be used outdoors with an enclosed clear glass fixture. Non-frosted glass is recommended so the photocell can detect the natural light. Plastic housing material with screw-in connection. 1.7" W x 3" L x 2.2" D.