Requires a pre-installed sight mod to mount. The magnification level can be changed while aiming down the sights, and the aiming FOV will automatically adjust itself. Not compatible with the Acough Optic, Military Red Dot, Milspec Scope, Combat Sight, Reconnaissance Sight, Theia Magnified Scope, Box Buddy Sight, the JP36's Original Sight, the Raven's Flip-up Sight or the GROM and Platypus 70's iron sights. Currently bugged and not appearing as intended on certain weapons, for a list see here. They're still listed below even if broken. Shows incompatibility with the Deagle's Marksman Sight, however they are allowed to be installed simultaneously.