Mike, although you can manually turn the sight on & off, this also has MOTAC™ (Motion Activated Illumination System)The ROMEOZero-PRO and ROMEOZero-R utilize MOTAC (Motion Activated Illumination System).
While the optic is ON, if no motion is detected for 2 minutes, the sight will automatically turn off to conserve battery life. As soon as the optic is subjected to the slightest movement, it will automatically turn on to the last brightness level and reticle option used.
Stay safe & have a great day!

Mike, yes sir, this includes the Romeo zero pro Wich uses sigs motac/motion activated. It also has Touch-Activated Programming) technology that gives the user the ability to change brightness with just a tap on the optic. Hope this helps.