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 Romeo1Pro 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) That Powers Up When It Senses Motion And Powers Down When It Does Not; Magnetac (Magnetic Activation) That 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 & Coatings) Technology Provides Ideal Reticle Brightness And Target Clarity While Using Gen3+ Night Vision Device