SunGuard uses the same anti-glint and anti-glare technology that is used by the U.S. Army, Marine Corps and Special Forces to camouflage their optics and cut the glare that interferes with clear sighting. ARDs fit easily into a standard scope cap, block sun glare from getting inside your scope and hide scope reflection that can spook trophy game. SunGuard ARDs are designed to mount to a scope by fitting inside a Butler Creek Flip-Open or Quake Bushwacker scope caps.