Designed for the most severe conditions, the Sig Sauer Romeo 8 2 MOA Ballistic Circle Dot Red Dot is ideal for rapid target acquisition in any environment. With MOTAC Motion Activated Illumination, this optic is ready when you need it, but powers off when not in use to conserve power. The lightweight CR123A Battery lasts up to 10 years on medium settings. Features: Designed for modern MSR platforms and shotguns Comes standard with solid lens covers and 1/2 hex bolt mount Ballistic Circle-Dot reticle options Users can select from 4 different integrated reticle options (Dot, Circle-Dot, Dot with Holds, Circle-Dot with Holds) 100,000+ hour battery life and the readily available CR123A battery is side loading for quick battery replacement. Unlimited eye relief to acquire aiming point and target, regardless of eye position behind sight. MOTAC (Motion Activated Illumination) powers up or down when sensing motion Uses an ultra-efficient red LED illumination for daylight visibility and extended runtime 1.535" Mount Height Strong, lightweight aircraft-grade 6061-T6 aluminum housing Waterproof, IPX-7 rated, and fog-proof.