The Adapter Plates for Osight X is (an accessory) compatible with Osight X. CH SGX-RSH-10-8 Adapter Plate (with built-in rear sight): Used for mounting Osight X on SIG SAUER P320 XFive Legion Series. CH SGRX-RSH-FIL Adapter Plate: Used for mounting Osight X on SIG SAUER P320 RX / Pro / AXG Series. CH SG69-RSH-FIL Adapter Plate: Used for mounting Osight X on SIG SAUER P226/P229 RX / Pro / AXG Scorpion Series. CH SG6L-RH-RSR Adapter Plate (with built-in rear sight): Used for mounting Osight X on SIG SAUER P226 XFive Legion Series. CH CZ-SDW2-RH-ZEV-RSR-ST Adapter Plate (with built-in rear sight): Used for mounting Osight X on CZ SHADOW 2 OR Series.