The SPD Combat optic has dual power modes, it can run off the Sun via the solar cell on top of the optic, or the onboard AAA Battery (included). Optic includes our Patented SwitchCover lens covers. PATENTS: US 9563050, CA 2881921, CN 201510067251, EP 2908084, PATENT PENDING Five brightness settings for the red dot reticle, in battery mode. Unlimited eye relief for flexible mounting positions on the firearm. Includes a low rail mount and a high quick release rail mount for mounting onto weaver/ Picatinny/ MIL-STD 1913 type rails. Compatible with most Aimpoint Micro Mounts.