This really hard to find mint condition Mamiya 7 Polarising Filter Adapter AN701 is probably new, and certainly unused. Mamiya part number # 4957672257996, 535081.
The ZE702 Polarising filter (on its own) can be fitted to the 67mm thread lenses (it has a bayonet fitting like the lens hoods – not a threaded fitting) – the 43mm, 50mm and 150mm. Howevere, for use with the 80mm and 65mm lenses you need to clip in the AN701 adapter. These are often lost which really restricts your use of the filter. If you have lost your adapter then you need this one.