Dusk-to-dawn sensor: built-in photocell light sensor turns the bulb on at night and off during the day; designed for use in an outdoor fixture that receives direct sunlight; cannot be used in enclosed fixtures Great for use in outdoor lighting fixtures with applications such as walkways, driveways/garages, porches and other areas outside of the home where light is needed at night. Start saving today with these energy efficient PAR38 Dusk to Dawn Sensor LED Light Bulbs. These lights have a E26 Standard base. These 120 watt replacement light bulbs use only 14 watts of energy, costing only $1.68 per year to operate. That is a saving of $116.21 in energy costs over life of the bulb compared to the incandescent equivalent (based on 3 hours/day, $0.11/kWh) 10,000 hour lifespan; lasting over 9 years (based on 3 hours of use each day) Daylight White (5000K) simulates daylight, providing a bright, crisp atmosphere for any room. Non-Dimmable LED Light Bulbs