Vortex Sparc AR Red Dot

From box and barricade drills to night shooting, the SPARC® AR is designed for high-speed tactical scenarios. Built to handle the abuse of repeated use, its 50,000-hour battery life keeps you going through long training sessions without a break. Compact and rugged, it's the workhorse that keeps you sharp and ready for every challenge, no matter how intense the pace.

Note: If you forget to turn off the SPARC AR, it will automatically shut down in approximately 12 hours.
(Text from the sellers page)

(its night vision compatible)