This sale is for a very rare Bronica ETR External Battery Case / Remote Battery Pack to fit the Bronica ETR series cameras. It is in near mint condition and includes the original instruction sheet with just a few rub marks on the battery connector from being carried around.
This external battery case is in superb condition, and you can download a copy of the Bronica case instructions from this website.
This case is designed exclusively for the Bronica ETR cameras for use in cold weather. It allows you to keep the battery inside warm clothing where your body temperature can maintain the battery voltage. It takes the same 6v battery as used in the camera.
No doubt you could also fit this in other cameras such as the Bronica SQ series and GS-1, or even Mamiya 645 cameras – anything that uses the 544 / PX-28 or equivalent battery with a similar battery loading system.