*Compatible with Glock MOS systems such as Gen4 17, 19, 34, 40, 41, 35 and Gen4 17, 19, 34*This red dot fits directly into the Glock MOS system with the #1 mount that comes with the MOS without the need to remove the rear sight.*Promotes rapid target acquisition while providing a precise point of aim; getting shots in range and on target quickly.Fits glock MOS System below 1. G17 Gen4 MOS 2. G19 Gen4 MOS 3. G34 Gen4 MOS 4. G40 Gen4 MOS 5. G41 Gen4 MOS 6. G35 Gen4 MOS 7. G34 Gen5 MOS 8. G17 Gen5 MOS FS 9. G19 G34 Gen5 MOS SF 10. G34 GEN5 MOS SF Glock is Constantly introducing add the MOS cut to your popular models, this list might be outdated. As long as there is a cut for red dot, it will fits.