The Sig Sauer ROMEO1PRO brings a new level of durability and performance to the miniature open-reflex red dot sight. Its aircraft grade aluminum housing ensures corrosion resistance under the harshest environments, and a new upgraded point-source emitter provides increased brightness in day or night conditions with 12 brightness settings. The molded glass aspheric lens has upgraded high performance coatings for superior light transmittance and zero distortion giving you fast, responsive target acquisition and accuracy. The ROMEO1PRO includes a ruggedized protective shroud in the box for extreme durability.ROMEO1PRO is Compatible With :- M17- M18- P320-M17- P320 XFive Legion- P320 XCompact- P320 XFull- All PRO-CUT Slides- P320 Pro SeriesMolded glass aspheric lens with high-performance coatings for superior light transmittance and zero distortion3 or 6 MOA red dot with multiple brightness settings for rapid target engagement under a full range of lighting conditionsTruHold Lockless Zeroing System that utilizes twin adjustment springs designed to endure handgun recoil and return to zero shot after shotPoint-source emitter provides exceptional brightness with 12 settings (10 Daytime/2 NV), and 20,000+ hours of runtimeMOTAC (Motion Activated Illumination System) that powers up when it senses motion and powers down when it does notAircraft grade CNC Aluminum housing ensures a lifetime of reliable serviceDependable waterproof (IPX-7 rated for complete water immersion up to 1 meter) and fog proof performanceRuggedized protective steel shroud included for extreme durabilitySIG SAUER Electro-Optics Infinite Guarantee and SIG SAUER Electronic Component Limited 5-Year WarrantyPlease note, this product is NOT compatible with slides cut to accept a standard ROMEO1. The ROMEO1PRO is NOT rated for 10mm.