This single replacement board is used wherever you want to replace old metal sockets with a 555 type bulb.. there are a lot of cases where you could replace a metal socket with another, but using a 555 type is more convenient, easier to change, or you prefer the 555 for your LED style base.
The board includes the diode, two standoffs, and two screws. Provide your own twist socket, or buy the socket separately on our web site.
