Sig offers many model variations and optic cuts. Calculated Kinetics optic plates support the Romeo 1 Pro Cut, with the rear side remaining after the optic cover is removed. These plates also fit the SIG P211 GTO. Their plates for these models feature a front dovetail that hooks under the slide, recoil lugs to prevent the optic from twisting left or right, and are hard anodized black for durability. They even manufacture 6-40 screws for this platform to include with the plates.Features :Fits Sig P211 and P320Designed for RMR Footprint OpticsIncludes Hardware, Torx Bit, Vibratite, and an Install Card