Molded glass aspheric lens with high-performance coatings for superior light transmittance and zero distortion; 2 steel shrouds included for 3 different optic configurations, including fully enclosed and sealed with a polycarbonate rear window; Shares the ROMEO1 PRO footprint, and can be direct mounted to any sig pistol with the pro slide cut; Spring-loaded side battery tray, released by a push button that can be activated without tools; MOTAC (Motion-Activated Illumination System) powers up when it senses motion and powers down when it does not; Magnetac (Magnetic Activation) automatically turns the optic off when holstered in a compatible holster, and instantly turns the optic on when drawn from the holster; D.A.R.C. (Dark Adaptive Reticles and Coatings) Technology provides ideal reticle brightness and target clarity while using Gen3+ night vision device; Fits all Sig Sauer pistols with the PRO RX footprint. Will not fit true Delta Point PRO footprint slides and mounts; Designed, developed, tested and assembled in the USA