While three dot iron sights are pretty good, the Holosun HE509 X2 Elite Reflex Sight with ACSS Vulcan reticle is almost guaranteed to help you improve your accuracy. This pistol sized Holosun red dot sight straightaway allows for a large field of sight and has those features which allow you to sight in quickly and acquire the target and the location you intend to hit. What's so neat about the Holosun HE509 is the entire sight system is fully enclosed in light and rugged aluminum, the HE509 Red Dot Sight protective housing stands head and shoulders above an open form reflex form factor. FeaturesLight and rugged aluminum housingAbrasion and shock resistantEnclosed emitter