Light bulbs for, among other possible uses, the tester shown in the photo. I have no idea what other uses these bulbs might have beyond the vintage tester shown.
I burned out one of the continuity testing bulbs. I was unable to find one locally, so I looked on eBay and found these. My tester now works as it has for the last 50 years.
My problem….your opportunity…..is that I intended to buy two bulbs, but I actually ordered twenty. Hence, I am offering them, for $1 each, to anyone who might have a use for them.
The tester is not for sale, but you can still buy them on eBay.
I will delete this posting when they are all sold.