The OPF-FN509T, RMR is a single-piece, billet-machined plate specifically designed for RMR/SRO optics. It is not guaranteed to be compatible with non-Trijicon sights that share the RMR footprint. The design of the optics plate for the FN 509 Tactical is somewhat unconventional, featuring a MIM or cast steel plate with lugs for the RMR, alongside a larger plastic component lacking lugs or mechanisms to prevent lateral movement of the sight. This is not a critique of FN's design, rather, we favor a solid-state design without moving parts. The OPF-FN509T, RMR is crafted with the same precision as previous OPF plates, ensuring tight tolerances between the plate and slide, as well as between the optic and plate. Factory FN 509 Tactical sights remain compatible with the OPF-FN509T, RMR, allowing for lower 1/3 co-witnessing. The OPF-FN509T, RMR package includes the adapter plate, two 6-40 x 1/2 T10 screws (identical to those in the 509 Tactical plates/screws packet, with FN-supplied screws also compatible with the OPF-509T, RMR plate) and a packet of VC-3 thread locker. A torque wrench is necessary to apply the correct torque value to the mounting screws. The torque specification for 6-40 x 1/2 inches T10 screws is set between 12 in-lb and 13 in-lb Meticulously crafted and manufactured in the United States, ensuring high-quality standards and exceptional attention to detail