This sale is for a new / unused Mamiya RB67 Power Drive Control Pack, suitable for use with the original model RB67 120/220 power drive backs, complete with original box.
This control pack holds the batteries and supplies power to the original type power drive backs. The original instructions are missing from this item, but can be downloaded from the Downloads / Mamiya Instructions section on this website – just look for “Mamiya RB67 Power Drive + Control Pack”.
You of course need to have one of these power drive backs to use this control pack, but there are plenty of them offered on eBay, usually sold as normal RB67 ProS backs.