I'm looking to buy a Rada 120 film holder in good condition, that will fit a 9x12 Voigtlander camera, e.g. Avus and Bergheil.
I heard they are fairly standard, slide in type. Since the 9x12 sheet film holders I have are marked Contessa Nettel
I'm based in San Francisco Bay area.
A little heads-up; Rada made 120 holders for a LOT of different cameras. Just make sure you are looking at the right one that'll fit your camera.
Rollex was another type of 120 film back made for various cameras by Balda.