Not very common. I use this extensively with my Edixa 16, when loading it with 25 or 50 ASA.

Size is 22mm, snap on type.

This is a Rada-style cassette, it fits Edixa 16.

Cut from a regular 35mm developing reel, very useful for my 16mm film processing. Did that because I could not find a suitable (and cheap) similar device to purchase anywhere.