Cold Harbour Media feature the  Photonis Defense Boomslang 50° Wide FOV lenses for expanding your NV's FOV... "In this video, Ryan goes over the new and hotly anticipated Photonis Defense Boomslang 50° Wide FOV lenses. We will be going through eye relief, accessories, resolution, gain, and more! Join us in this video for all things Boomslang and see if these are the next big upgrade for your NV setups."

DYE i4 is a familiar full face mask or eye protection amongst paintballers and airsoft players in the USA and there is a way to change lenses to fit the lighting conditions of the game site. All Star Airsoft shows you how to do this yourself in just 3 minutes.

We need more information with regards to this as there was no description provided by YZH on these lenses which can be used as replacement for the Emerson FAST Helmets with Goggles already included. We can't say if these are three types of lenses or this is a photochromic ones, with the photos showing the various shades of the photochromic lens under different lighting conditions. If photochromic, no need for changing lenses.