Whether in airsoft or out in the woods, shiny stuff is really easy to spot. The front of your flashlight is a large perfectly reflective device. Adding a ARD can greatly reduce the angle at which the shiny mirror surface can be seen by anyone viewing your location. 

The cap can also be used to ensure even accidental button presses won't reveal your location.

This is similar to ARD caps put on scopes or other aiming devices. With some adjustment, you should be able to scale these models to any need. 

Ensure you measure both your flashlight (or other item) front end and ensure proper tolerance for good fit. 

I used 1/8" inch Shock Paracord to string through to ensure a secure rentention of both the ARD and cap.

The killflash set includes previous versions and smaller grid patterns. These ended up being too fine and unnecessary. The stand-alone ARD files are preferred.