The Railway series has a standard rail base pre-installed to allow the sight to be attached to most Weaver or Picatinny rail mounts or receivers. This sight can mount to just about anything with a rail mount installed including shotguns, rifles, handguns, revolvers, crossbows, paint ball guns. The rail base is detachable allowing other bases to be installed, or with no base installed the sight to be used as a Slide Ride model for direct mounting.
The Tactical Railway models have a Tactical Spacer Kit installed. When mounted to AR15 / M16 / M4 flattop rifles and carbines, they will co-witness the iron sights in the lower 1/3 of the lens. The standard Railway models will co-witness the iron sights in the center of the lens.