GU24 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 uniquely-shaped 13 watt GU24 squat spiral offers 900 lumens of light, which is equivalent to a 50-60 watt incandescent.