This plate will attach to an RMSC optic mount, and allow you to mount an RMR optic to the adapter plate. This comes with the screws to mount the plate to your device. It does not come with screws to mount t the optic, use the screws provided with your optic to mount to the adapter plate. *DOES NOT FIT 1911 SLIDES and does not fit some 2011 slides **Fits with the standard mounting screws for the RMR optic pattern – Holes are 6-32 tapped holes (standard for RMR) Simply attach this adapter plate on the existing RMSC optic cut as a regular optic plate. Screws are provided for mounting the plate, with pre-applied loctite. (Provided screws are M4x.7, and 6-40. Test fit your screws, be sure your using the correct screw, some manufactures use uncommon hole threads) Compatible with all RMR Optics: Example Compatible with Trijicon RMR/SRO Holosun407c/507c/508t/509t/EPS and ANY RMR footprint optic Holes on the plate are tapped to fit the standard thread for RMR – which is 6-32 thread type holes. The plate comes with 2 sets of screws, M4x.7 and 6-40. **PLEASE CHECK YOUR FITMENT!!!! ADAPTER IS OFTEN RETURNED BECAUSE OF THE FOLLOWING REASONS: YOUR SLIDE IS NOT RMSC PATERN AND DOES NOT FIT, make sure your slide has a RMSc cut on the top. SLIDE IS Not a true RMSc-spec footprint, or Modified, or From manufacturers whose RMSc cuts vary from industry spec (BUDGET SLIDES) This can cause compatibility misunderstandings even though the product is functioning correctly. MAKE SURE YOU HAVE THE CORRECT FITMENT BEFORE PURCHASE!!!