Vism by NcSTAR | SPD Solar Reflex Sight | BLACK | SPD has a dual power source. The Red Dot reflex optic can be powered by the sun via the top mounted solar cell or the included AA battery.
Red Dot Sight with 4 Reticles
Red Dot & Green Dot Four Reticle Reflex Optic BLACK
NcSTAR DDAB Micro Red Dot Optic w/On/Off Switch | Includes Extra Battery, Lens Covers, and Mounting/Adjustment Tools