Originally designed for the AR15 type Airsoft guns, this mounts on-top of the receiver rail and provides a 25mm (1 in.) higher rail for lifting any aiming devices like a red-dot sight higher, making it more comfortable for shooters wearing full face masks.
It is perfectly centered on the top rail and features a see-through tunnel, allowing the use of back up fixed sights. 2 mounting screws are included to secure certain sights systems which features matching threaded holes.