The .87" RMR Low Riser allows you to mount RMR footprint pistol optics to any rifle or shotgun with a Picatinny rail. The CNC machined 6061-T6 Aluminum with Matte black Type 2 Hard Anodized finish ensure a solid direct slide-to-optic connection. Comes with mode-specific screws with Loctite pre-applied.The co-witnessing 1.54" RMR footprint High Riser allows you to mount RMR footprint pistol optics to any rifle or shotgun with a Picatinny Rail. The CNC machined 6061-T6 Aluminum with Matte black Type 2 Hard Anodized finish ensure a solid direct slide-to-optic connection. Comes with mode-specific screws with Loctite pre-applied.