Rolleiflex 6000 series External Battery adapter (Used but Excellent)
This adapter has a battery receptacle and plug that allows you to mount the battery further away from the camera - to save weight, or to keep the battery in a warmer location such as a pocket, etc. Will work also with the Rollei Lens Control S
It's not a battery just an extension cable - and a battery is not included. Condition is excellent, lightly used with almost no marks. I've never seen another one, so not sure how common they are.