This sale is for a really excellent condition and very rare Mamiya 645AF External Battery Case to fit the Mamiya 645AF, 645AFD and Phase One cameras. The instruction sheet is missing – which isn’t really a problem as you can download it from this website anyway.
This case is designed exclusively for the Mamiya 645AF / Phase One cameras for use in cold weather. It allows you to keep the batteries inside warm clothing where your body temperature can maintain the battery voltage. Or – if you have broken the AA battery cage on your 645AF series camera, this will get you out of trouble. Seeing as some sellers are charging £200+ for a battery cage, this is a way cheaper option.
Please note that the end of the battery holder in this external case is a different shape to the one in the camera, so you cannot use the holder from this case directly as a replacement for a camera battery holder.