Our ATACR(TM) 4-16A-42 F1 was created to maximize the potential of precision semi-automatic rifles-a need identified by U.S. military and civilian shooters. It is designed for rapid target engagement, with a low profile and an overall length of just 12.6 inches.Like all Nightforce ATACR(TM) riflescopes, its ED glass produces images of striking brilliance and clarity. ZeroHold(TM) technology provides an instant return to your chosen zero and also allows dialing below zero. A wide range of intelligent first focal plane reticles, in MOA or MRAD configurations, address virtually any shooting environment.