Spuhr Cantilever Interface Mount Rings 38mm Black. The SCP-3022D is designed for use on Picatinny rails and features two interface ring which can be rotated as to position the interface/accessory in either the 12-o'clock or 3-o'clock position. The SCP-series of mounts feature two separate side clamps and the SCP-3022D allows the scope to be mounted 70 mm/2.76 further forward than with a non-cantilever mount. Specifications for Spuhr Cantilever Interface Mount Rings: Manufacturer: Spuhr Color: Black Package Contents: Spuhr Cantilever Interface Mount Rings Spuhr SCP-3022D: Cantilever Interface Mount Rings 38mm Black