The open reflex ROMEO3 sight is the ideal sighting solution for MSR rifles, shotguns, carbines, submachine guns, and full size handguns. Our proprietary red-notch coating ensures a bright red dot. ROMEO3 is perfect for those moments when you barely have time to blink. The readily available CR2032 battery is side-loading, allowing for quick battery replacement without having to remove the sight from the firearm. Extremely strong and lightweight aircraft grade CNC Aluminum housing ensures a lifetime of reliable service. Dependable waterproof (IPX-7 rated for complete water immersion up to 1 meter) and fog-proof performance.