Product Features:

Front side: M28.5x0.6 female thread (astro 1.25? filters)
Rear side: 1.2?-32tpi male thread

These will work with PVS-7, PVS-14, or any device using ENVIS lenses.

The adapter allows you to use filters like the Baader 612nm band pass filter (great for reducing light pollution and bringing out nebula even under semi-urban skies) and the Astronomik 12nm H-alpha filter (which will show brighter nebula even under very light polluted skies).

The adapter can also be threaded into the snap-on mating collar on the 3x and 5x afocal lenses, meaning that you can put these in some spare mating collars and just snap the mating collar with the thread you need on and off your device.

1.2_-32tpi (M30.3x0.8) to 1.25_ astro filter (M28.5x0.6) adapter for ENVIS lens