My old Cities Service sign with the cats eye marbles in it is missing one marble and I'd dearly love to find a replacement!
Tough part is that it is "RED" in color!
I've attached a picture to show what it looks like.
The metal case has "libbey" imprinted on the back, so I suppose it must be the brand name?
I just think there is one floating around out there somewhere?

Kevin are these the right size? Cats Eye marbles

No, too small. I checked thru all the ebay listings and couldn't come up with something even real close? As far as I can tell without buying a fancy digital caliper, the hole is 7/8 of an inch in diameter. I neglected to measure the length before I put it back together, but it seems they are all about the same length?
Maybe the brand "libbey" will be the key? It was stamped with that name on the back.

Not sure if this will help, but I will offer what I have researched on these cateye reflectors. The older (late 1920s ~ patent pending) libbey reflectors are very hard to come by like the one you have, I have only been able to find some green ones, and been shopping for these constantly over 3 years.

In the 1930s manufacturers went different sizes and style than the one you have pictured...and somewhat standardized their sizes. The most common manufacturers are Libbey, National Colortype, Persons, and Signal. All four of those manufactures used a number system of 1-5 (National Colortype used 11-(followed by a digit) to 15-1) to indicate the sizes. I know Libbeys, Signals, and National Color Types will all be marked on the back.

I hope my sizing chart uploads for reference. These are later style libbeys which would be held in place with a mounting cap on the back side. Smallest is a Libbey #5 (17/32), Largest is a Libbey #1. I believe you could make a #2 work the flange appears wide enough to hold. The #1 will not fit a 7/8's mounting hole.

Thanks

Wowser! Talk about information! I am so impressed by your knowledge of these little light reflectors!
It doesn't give me much hope if you have been hunting them for 3 years, with no luck! LOL I can live with a single reflector missing, but it is such a great sign, that I would desperately like to replace the missing one.
I will send you a PM, so that we don't tie up the wanted section talking about these things! Thank you so very much!

Just put a patch over it until you find one!

Remove 1 at bottom center to replace upper one, till 1 is found.

this is what I'd do temporarily.. went by and seen a guy today that I know who has a collection of cat eye marbles,
said he has different size red ones but there in storage-
will follow up on this as he is doing some metal fabrication work for me...as long as your in no hurry we'll eventually get you one & if you get one before I do let me know...

Thanks Randy! No hurry, as it took me 3/4 of a year just to clean the sign up and get it mounted on a nice base! Hopefully the fellow will have what I need. 7/8 inch hole and is a Libbey brand. Looks like the one I pictured at the start if this post!