Please...don't confuse AE Prism 'II,' with the non-metered Model '2,' prism.
(Mamiya makes a major [confusing] distinction in their RZ Prisms,
employing both conventional numbers, or Roman numerals).

Check manual pages 18-19 (PDF pages 21-22) from an
RZ accessory manual provided by the 'Butkus Manuals Site.'
http://www.cameramanuals.org/mamiya_...ccessories.pdf