This strong rails is purpose-made for the FX DRS PCP air rifles and accepts riflescopes with 22mm picatinny/weaver mounts. Mounting these rails is very easy because they simply slide over the 11mm rails of the FX DRS. You then secure it with the supplied locking screw.   30MOA/9MRAD cant The rails have a built-in tilt of 30 MOA/9MRAD. This causes the scope to tilt slightly forward. This allows the scope to be further adjusted to longer ranges than the standard adjustment range allows. This is especially a desirable feature when shooting at long distances.   The FX DRS 30 MOA High Weaver/Picatinny mounting rail is CNC machined from black anodized aluminium, ensuring very close tolerances.