This thing that looks like a honeycomb board is not used to raise bees, but an optical equipment anti-reflection device (ARD), referred to as ARD, developed by an American company called Tenebraex. The registered trademark is called "killFlash?", which means kill flash. In military history, there are always some unlucky people who lost their lives and failed their operations because the light reflected from the telescopes in their hands and the sights on their sniper rifles exposed their positions. In Hemingway's "The Bell Rings", the protagonist holds the front end of the telescope with the tiger's mouth, so that the broad palm forms a hood on the telescope. This is a crude and practical method for the telescope, but if it is used on a gun sight, It is inconvenient to use this method. The current traditional anti-reflective method is to put a cylindrical visor in front of the lens. However, the visor itself is both long and long. It is difficult to imagine a squad/platoon leader carrying a low-power telescope the size of an astronomical telescope to command the battle. . In addition, for snipers, there is still a way to hide a visor, but now more and more low-magnification or no-magnification optical sights are used in foreign military and police forces. The AOCG used by the US military's conventional infantry As is increasingly common with CCOs, it is inconvenient to add a large, thick visor to a lightweight assault weapon. killFlash?ARD was developed under this background. KillFlash?ARD actually uses traditional sunshade principles, but its structure and materials are novel. Its structure is made of a Nomex honeycomb-shaped porous circular plate reinforced with resin material inside a short aluminum cylinder, which looks like a honeycomb-shaped porous filter plate. When light passes through these small holes and hits the mirror, it is difficult to form a strong large-area reflection, just like installing countless tiny sunshades in front of the lens. However, this Columbus egg-shaped idea and production materials have been applied for patented. According to official promotional materials, taking the lens of an M144 sniper scope with a diameter of 74mm as an example, the effect of a killFlash?ARD is equivalent to that of a traditional visor tube 889mm long. However, there are gains and losses. The disadvantage of killFlash? ARD is that this honeycomb filter plate will reduce the light transmission rate in front of the lens. It is said to be reduced by about 15. But in any case, killFlash?ARD's concealment made it favored by special forces as soon as it came out. The US military's special forces were the first to install killFlash?ARD on their ACOG. Now it has been adopted by other conventional ground combat forces. killFlash?ARD is an anti-reflective material installed on telescopes and sights.