four little metal KODAK film canisters

I've never seen *little* metal film canisters like these though the larger size is common -- the red one w/yellow top (and a quarter coin) are pictured here as size reference to show that these four (yellow w/red tops) are about half the diameter (but same height) as the typically found ones. I don't know what particular type of film they were intended to hold, or if there's a particular reason why they are smaller than usual.