Originally Used to put a coin in for the meters or hold trunk key I think.
Era: not sure -- but think 1970's (Pre 1980's for sure) .
Pocket is tiny but If you have a pill tiny room for possibly small asprin, nitro for heart , or ?
I do have in other automobile ID keychains.. just ask and will list if I have.
If buying more than one an automatic discount is set to be applied.
If you need two different.. ask and will make a special listing so you can still get the discount.