The Sig Sauer ROMEO-X Reflex Sight is the result of our experience developing durable red-dot technology that's trusted by the military and put into a streamlined civilian package. Featuring a CNC 7075 aluminum housing, intuitive adjustment buttons, a side-mounted battery compartment, and an ultra-low deck height that gives you the ability to Co-Witness with standard height iron sights. Designed, tested, and assembled in the USA, the ROMEO-X boasts direct mounting footprints for your favorite optics-ready pistol. 10mm rated. The Sig Sauer ROMEO-X PRO is suited for the optic ready P320, P226 & P229 Family of pistols Inspired by Mil-Spec ROMEO-M17 CNC Machined 7075 Aluminum Housing Patent-Pending Beryllium Copper Flexure Arm Distortion Free Aspherical Lens Open Emitter MOTAC (Motion Activated Illumination) Circle Dot With Individually Selectable 2 MOA Dot & 32 MOA Circle Low Deck Height for Standard-Height Iron Sight Co-Witness 20,000 Hour Battery Life With Side Load Battery 15 Illumination Settings Including 3 Night Vision Assembled in the U.S.A.