With a regular polarizer on a range finder, you typically hold the filter to your eye, rotate to the desired position for the effect you wish, then carefully screw it to the front of the lens so as to keep the exact orientation or risk loosing the effect desired. I found it impossible to do. I've heard that some resort to marking the filter for the correct orientation so that they can set it to the same orientation after screwing it into the lens. I never figured what this was all about! There may be a better way of doing this that I never doscovered.
The mamiya ZE702 filter solves this very easily. The polarizer is designed to flip up so that you can preview the rotation while still attached to the lens. You then flip it back down over the lens and it keeps the orentation precisely. It's actually very well designed. It makes using a polarizer on an RF really easy...