[Fred R]

Very simply, a pilot light. There was a plastic jewel that went in there. I use to have a 42-1015. I used to be able to get red jewels from when I was in the vending business years ago. It was for a "use coin only" light. I used the little piece from the top of a red Bic pen in some cases now. It's not transparent like the originals but works. The originals disintegrated and turned to powder which is why they are always missing.