This sale is for a brand new, unused and unmarked Beattie Intenscreen with 90 degree (horizontal) split image # 83312 for any Mamiya RB67 camera, complete with original box and instructions.
This is the best screen for ease of focusing. A very very rare screen. And to find a brand new example is near enough impossible.
It gives around 2 to 2.5 extra f stops of brightness in the viewfinder. You can find loads of information about Beattie screens in the Downloads/Miscellaneous section on my website. It will be very securely packed for shipping.