Hi there, I recently acquired a used Thomas Duplex Safelight for my darkroom. The safelight is in great shape except the bayonet mount for the sodium vapor lamp got split/broken in transit. I am thinking that this is an easy part to just swap out, but I am unsure what type/industry size this lamp socket is. Sadly all documentation I have from the late Thomas company makes no mention of what part this is. Does anyone know what size of lamp socket this is? Thanks in advance.