This red dot uses the Shield RMSc footprint standard. Essential info Footprint standard: Shield RMSc footprint standard Reticle: 2 MOA dot & 32 MOA circle [red] Window size [height x width]: 14.0 x 21.0 mm [0.55 x 0.83"] Total dimensions [length x width x height]: 40.5 x 25.0 x 24.5 mm [1.59 x 0.98 x 0.96"] This red dot uses the Shield RMSc footprint standard. Features S-uper Compact, S-uper Power, S-uper Precision! Industryʼs First Magnetic Charging Cover: The Osight S boasts a pioneering Magnetic Charging Cover featuring a battery display that reveals the real-time battery levels for both the cover and the optic, making uncertainty certain. (The magnetic charging cover can fully charge Osight S 3 times, with each charge completed in 1.5 hours.) Enclosed Optic with Aspherical Lens: Designed with a fully sealed system, the optic offers unmatched protection against environmental elements. Its aspherical lens ensures zero distortion and parallax-free performance, delivering exceptional clarity through the large window for rapid and precise target acquisition. Multi-reticle System (2 MOA Dot & 32 MOA Circle): Switching between dot-and-circle, dot-only, or circle-only reticles, you can tailor your aiming solution to any usage scenario. The sharp and bright dot-and-circle reticle provides a cutting-edge aiming experience (suitable for outdoor activities, shooting training, and night patrols). Universal RMSc Footprint: Fitting directly to your optics-ready slides, the compact optic delivers exceptional compatibility, ensuring seamless integration across a multitude of builds. First Optic Made of OAL™ Material: The OAL™ housing is tough, strong, and nearly as lightweight as 7075 aluminum, with a Level III anodized finish that provides superior impact and corrosion resistance for lasting durability. Osight models have been field-tested with over 100,000 rounds, maintaining reliability and holding zero throughout.