The TW-Series AR2PRM Scope Rail Mounts with Upper Rail from BSA Optics provides a stable Picatinny/Weaver mount for 1" diameter barrel scopes. The two-piece set provides a great amount of placement versatility on your rail. Depending on the scope you use, and the eye-relief, you can place each scope mount where it best fits you, your scope, and the available space on your rail. The mounts provide a 20 MOA rise from the rail. One of the scope mounts has a 43mm long Picatinny/Weaver rail on top of the scope hole for an illuminator, small reflex sight or any accessory that will fit. You can locate this as the front or rear mount to further customize the accessory use. The aluminum mount comes ready to install in clamshell packaging.