The Trijicon RMRA(R) HD is an innovative red dot pistol optic specifically designed to meet the evolving needs of Law Enforcement and the Military. Built on the foundation of the Trijicon RMRA(R) Adjustable LED model, the RMR HD features the same patented housing shape made from forged aluminum, robust electronic system, and high-quality lenses. Key Features Top-Loading Battery: Easy battery changes without dismounting the optic. Uses common CR2032 battery with up to 3 years of battery life. Upgraded Windage and Elevation Adjusters: More tactile and audible clicks for tool-less zeroing. Rugged, Durable Construction: 7075-T6 forged aluminum housing. Waterproof up to 66 ft. (20 m). Large, Unobstructed Field of View: Parallax-free design for easy reticle acquisition. Reliability for Everyday Carry: Unique shape diverts impact force to protect lens from drops and bumps. Complete User Control Illumination Settings: Nine brightness settings with multiple modes for visibility in any lighting condition. Clear Target Visibility: Advanced lens technology for a crisp field of view. Identical Footprint as RMR: Mounts easily on popular red-dot-ready pistols using the same base as Trijicon RMRA(R). Improved Controls: More tactile and audible feedback for use with duty gloves. Index Ridge Alignment Aid: Built-in index point for fast sight picture acquisition even from atypical positions. Button Lock-Out Mode: Secures the Auto-Brightness Setting ideal for everyday carry. Manual Brightness Lock-In Mode: Secures the user-chosen brightness setting indefinitely. Brightness Response Setting: Options for Normal Auto (default), High Auto, and Low Auto adjust settings. Forward Mounted Light Sensor: Enables the RMR HD Automatic Brightness mode to read lighting conditions at the target. Advanced Features Reticle Options: Switch between a complex reticle or single crisp dot, both with a new super bright setting and an additional night vision setting. Auto Illumination Adjustment: Forward looking light sensor gauges brightness at the target and adjusts reticle brightness accordingly. Market Leading Illumination Adjustability: Allows operator to adjust the Auto Illumination and the dot/circle contrast for optimal visibility. Product Details Model: Trijicon RMR HD Reticle: 3.25 MOA Red Dot, 55 MOA Reticle Battery Type: CR2032 Battery Life: Up to 3 years Housing Material: 7075-T6 Forged Aluminum Waterproof Depth: Up to 66 ft. (20 m) Mounting Footprint: Identical to Trijicon RMR Brightness Settings: Nine settings with multiple modes