Description Sig Sauer Romeo 4S Compact Red Dot Sight, 1x20mm, M1913 Rail Interface The Sig Sauer Romeo 4S Compact Red Dot Sight offers an unmatched 1x20mm viewing experience with its M1913 Rail Interface, providing the precision and reliability required for any shooting situation. Features Designed for modern semi-automatic pistols, MSR platforms and shotguns Short and medium range engagements and recreational shooting across a wide range of calibers and light conditions Extremely strong and light CNC aluminum housing Runtime in excess of 100,000 hours with solar and battery usage Comes standard with see-through lens covers and quick-release mount Ballistic Circle-Dot and Ballistic Circle QuadPex reticle options Users can select from 4 different integrated reticle options (Dot, Circle-Dot, Dot with Holds, Circle-Dot with Holds) 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 True co-witness QR mount and low mount included Strong, lightweight aircraft-grade CNC aluminum housing Waterproof, IPX-7 rated, and fog-proof.