GU-24 light bulbs do not have the usual screw base, but instead have two bayonets protruding from the base. These insert into matching holes in the fixture's socket, and twist to lock into place. Twist and pull, and the bulb comes right out of the socket. This 18 watt GU-24 spiral offers 1,350 lumens of light, which is equivalent to a 75 to 90 watt incandescent. Light Output: 1,350 lumens (75-90 watt incandescent equivalent) Color Temperature: 2,700 degrees Kelvin (warm white) Color Rendering: 84 CRI Rated Life: 10,000 hours Dimensions: 2.3 inches x 4.6 inches