"Brenda Ann" wrote in message
...

The openings they fit into are ~11/16" (1.7cm)



It looks very similar to the bulb holders used by Heathkit for illuminating
their meters e.g on the SB220 amplifier.

A similar type of fitting was used for car dash board lamps on some British
cars until about the 1990's. May still be used on some models.

A trip to the local car breakers may be worthwhile.