The RMR/SRO mounting kit fits the Glock MOS slide and the Springfield OSP pistol. For the SRO, only the screws in this kit are required for proper mounting. Fits G17 Gen4 MOS, G19 Gen4MOS, G34 Gen4 MOS , G35 Gen4 MOS, G40 Gen4 MOS, G41 Gen4 MOS and Springfield OSP. Includes- sealing plate, two optic mounting screws (short) and Hex key.