First of all it is very difficult to find an E12 to E17 adapter. Unfortunately I had two problems with them, one on each end of the adapter. The E17 base is short, so when the bulb is screwed in, part of the "living" base remains open. Another problem is that they are constructed by soldering an E17 plug to an E12 socket and wrapping it in heat shrink tubing, but the socket won't screw in deep enough unless some of the tubing is cut off. For a more secure commercial solution I used 2 adaptersβ¦