This dimmable, 39-watt bulb creates crisp, soft white lighting for inviting indoor or outdoor living spaces. Versatile for multiple applications, this 2900-Kelvin bulb is ideal for use in indoor recessed cans and track lights, as well as outdoor spot light fixtures. Dimming feature makes it easy to create the right ambiance for any activity. Features a Medium Screw base. Flipping the switch immediately lights your room to full brightness; no slow starting or waiting. Philips reuses as much glass and packaging material as possible, reducing environmental impact. This bulb replaces 50-watt incandescents, with an estimated annual energy cost of $4.70 (based on three hours/day).