These NVG Depth of Field Adapters are exactly what the EOD Tech needs while working on IED's under NVG's.
After serving on the CIF out of Panzer-Kaisserne, I learned quickly I hated pinning while wearing NVG's. These NVG Depth of Field Adapters would have made my job much faster.
Put on your Nods and hold your hand in front of your face. Without the adapters, your hand is blurry but with the adapters you can read a book, balance your checkbook and pin devices.
If you're running a dual tube system, keep an adapter on each lens but with different size discs/holes.
The smaller the hole, the greater the depth of field or the distance from your nose to infinity. Without the adapters you'll see great if what you're looking at is about 20 feet away. Everything in front or behind it is blurry. When you add an adapter, the range of clear vision increases significantly in front of and behind the 20 foot mark. This gives you the ability to really see what you're working on.
One of my favorite tools for working in Low/No Light.