Sig Sauer Closed-Emitter Reflex Sight

From the Amazon Listing

• SIG SAUER RED DOT SIGHT - The fastest, most accurate, ultra-compact micro reflex sight, the ROMEOZero 1x24mm pistol sight has been optimized for everyday concealed carry and pistols with slim slide profiles; Enables rapid target acquisition; Parallax free
• RUGGED & DURABLE - This red dot sight features the SpectraCoat HD Polymer Lens with 10 times the impact resistance over traditional glass lenses; Rugged WeaponsGrade textured polymer body gives this pistol sight a great level of drop protection
• HIGH PERFORMANCE - MOTAC (Motion Activated Illumination System) powers up when it senses motion and powers down when it does not; Highly efficient, point source LED emitter provides a crisp dot that is 8 times more efficient than conventional red dots
• COMPATIBILITY - Direct mount to ROMEOZero; Shield RMS-c footprint; J-Point footprint; This handgun sight is NOT compatible with slides cut to accept a standard ROMEO1; Housing optimized for use with Polymer pistols, concealed-carry and slim slide profiles
• SPECIFICATION - Magnification: 1x; Objective Lens Diameter: 24mm; Battery: (1) CR1632; Reticle: 3 MOA Red Dot; Overall Length: 1.6 in; Overall Width: 0.93 in; Height: 0.93 in; Weight: 0.4 oz; Illumination Settings: 8 Daytime; Run Time: 20000 hrs