at3 tactical aro absolute cowitness riser mount - compatible with aro, fastfire, and venom red dot sights at3 tactical the at3 aro's absolute cowitness riser is a great option for using a micro red dot sight on a modern sporting rifle. this riser features a lightweight, cantilever design for a unique look and rock-solid function. since most micro red dot sights don't feature a mount at this height, it's a great option for gaining a wide field of view, and gaining function with backup iron sights or red dot magnifiers.