I have had a need for a replacement light socket for the liscense light on my '51 Chevy since I have had it as the socket was worn out and rusted out. the parts store clip-in sockets wouldn't clear the resessed ( from the top ) area on the bottom. then I found these, they are expensive at $23.99 each but there billitt aluminum and high quality. they use a 7/8" nut on the back to hold them in and mount in a standard 3/4" socket hole... mine came today and I installed it, using the original bulb number in 6v it works perfectly... I also had to replace 1 taillight socket in my Rambler, as it held the bulb loose and disn't always make contact, so I ordered 1 of the dual filiment versions, and installed it also.. again, works perfect except it does not seem to fit my 1157 bulb, on the internet it says they fit a 1077,1157 but in the instructions it only lists 10007, 1077 and the amber colored of the same.. so I'm going to the parts store tomorrow to get a 1077