This rear sight is made of polyfiber. It can be mounted on Mil-STD 1913 Picatinny Rail. It comes with flip up function and both Pistol and Rifle Aiming sight are installed. Users can choose Rifle or Pistol Aiming whichever they prefer. It is fully compatible with aftermarket airsoft guns. The patent design of this sight has been granted. Installation of this sight is easy and friendly.