Trijicon AC32064 RMR Mounting Kit For Glock MOS and Springfield OSP Models This kit includes the sealing plate and proper screws needed to mount an RMR on the Glock MOS and Springfield OSP slide Fits G17 Gen4 MOS, G19 Gen4 MOS, G34 Gen4 MOS , G35 Gen4 MOS, G40 Gen4 MOS, G41 Gen4 MOS, and Springfield OSP The AC32064 kit includes: RMR Sealing Plate, two RMR Screws (short) and Hex Key RMR optic not included One must have this kit to mount an RMR on a MOS slide - RMRs ship with two long screws which will NOT work; You will need the two short screws in this kit