E17 to E26 Light Bulb Socket Base Adapter Converter - Converts Intermediate Socket (E17) to Medium Socket (E26/E27) (Pack of 2) Easy to install. Simply screw the socket adapter into E17 type socket, and then screw in an E26 bulb. Enlarge the light bulb socket. Enlarge the intermediate socket (E17) to medium socket (E26). Widely used. Works with incandescent, CFL (Energy Efficient) bulbs and LED bulbs. Made with high quality material,Generates low heat Pull up the inner copper sheet for better contact with bulb's base