Rollei MRC 120 Remote Release (used) - can do multiple exposures
The MRC remote release is different from the Regular RC-120 in that it has a single exposure/multiple exposure switch. So it can work without advancing the film if you want to do several exposures. These are not all that common to find, and so I've pasted a little bit about how this works from the Jan Boettcher at Rolleiclub below:
"I checked with one of my MRC 120 and one of my SLXs. The MRC 120 has two buttons, "mirror" and "start" plus a switch "SE"/"ME"
Switch to "SE": "mirror" fires the mirror upgreen LED flashes once "start" releases the shutter (no matter if the mirror was up or not) followed by film transport and instant morror return.
Switch to "ME" red LED next to "start" lights up: "mirror" fires the mirror up, The green LED flashes once "start" releases the shutter (no matter if the mirror was up or not before, it stays up after exposure) press start more often to take more exposures setting "SE"/"ME" back to "SE": Film gets transportet, mirror returns down (red LED goes off)"