Monstrum Stainless Steel RMR 407C/507C XR Mounting Plate for Optics Ready Glock Pistols for Full Sized and Compact Gen 4/ Gen 5 MOS. The mount is built for use with: Gen 4/Gen 5 MOS version Glocks including G17 G19 G22 G23 G34 G40 G41 G45 and G47 NOT compatible with: Non-MOS version Glock pistols G43x/G48 Slimline MOS version Glock pistols Compatible with RMR footprint red dots only. Please refer to the compatibility chart graphic before purchasing. Includes M3 screws in multiple length for compatibility across different red dot makes and models. Recommended torque specs : 15 in/lbs. Monstrum Real Steel Series mounts are crafted from stainless steel and electrolysis treated for corrosion resistance. Steel is a more durable material than aluminum providing 1) more rigidity against recoil 2) more resistance to extreme temperatures and 3) less susceptibility to stripping. All Monstrum products come with a lifetime guarantee Package Contents: Monstrum Stainless Steel RMR 407C/507C XR Mounting Plate for Optics Ready Glock Pistols Monstrum ZD44R-STL: Stainless Steel RMR 407C/507C XR Mounting Plate for Optics Ready Glock Pistols for Full Sized and Compact Gen 4/ Gen 5 MOS