Sig Sauer ROMEO 4T-PRO Red Dot Sight is a tactical battery powered red dot sight designed, built and tested for hard, professional use.Designed for modern semi-auto pistols, MSR platforms and shotguns Short and medium range engagements and recreational shooting across a wide range of calibers and light conditions. Designed, built and tested for hard, professional useEngineered lens coatings for elite performance in bright light or NVTop mounted activation with NV Override controlQuad Ballistic Circle DotDurable half-inch hex mount9 Daytime settings, 3 NV settings3 mounting heights come standard in the boxIncludes clear flip-backs, opaque front flip back, and ARD Kill-Flash50,000 hr runtime with CR2032 Battery and MOTACAssembled in USA