SIG SAUER Inc. has a Rotary Diopter Sight System optimized for the SIG556 rifle. The sight system provided four site stations for accurate engagement at varying distances including CQB, 100m, 200m, and 300m, all with tool-less windage and elevation adjustment. Designed to work in conjunction with the hooded front sight, the Rotary Diopter Sight System attaches to the receiver's M1913 rail. Made of durable steel construction the Rotary Diopter Sight System retrofits all existing SIG556 rifles. The front and rear sight co-witness with the SIG SAUER Mini Red Dot Sight and are optimized for M855 and M193 ammunition. The Rotary Diopter Sight System features 0.5 MOA click adjustments and 34-inch windage/25-inch elevation adjustment range at 100 meters.