The Umarex Optic Adapter Plates for Glock Type MOS 1 Air Pistols are engineered to provide a secure and reliable attachment method for popular optics such as a red dot sight to the MOS-ready slide on an officially-licensed Umarex Glock Type MOS 1 air gun or airsoft pistol. This package includes four MOS (Modular Optic System) adapter plates that work with optics that have these footprints: Trijicon SRO, Vortex Viper/Docter Sight C, Leupold Deltapoint/Shield RMSx/c, and C-More STS 2. It will not work with Type MOS 3 air pistols.