This is for 70s EM & SS.
I need to get a few of these, and am trying to figure out what the correct part is.
The Pinball Resource only seems to have this, and which is listed being for the backbox lighting:
http://www.pbresource.com/sockets.html
http://www.pbresource.com/sockit/gtb-a1363.jpg
Marco's has a few:
(OUT OF STOCK): https://www.marcospecialties.com/pinball-parts/A-8262
https://www.marcospecialties.com/pinball-parts/077-5000-00
(OUT OF STOCK): https://www.marcospecialties.com/pinball-parts/E-120-176
The one listed at The Pinball Resource claims to be compatible with Bally E-120-176, which would match the last one @ Marco's.