Holosun HS510C Open Reflex Red Dot Sight (Multi-Reticle System, Solar Failsafe, QD Picatinny Mount)
The Holosun HS510C is a 1x open reflex red dot built around a large window and an integrated quick-detach Picatinny mount (co-witness height depends on configuration/spacer). It uses a 650nm LED emitter with a selectable Multi-Reticle System (2 MOA dot, 65 MOA circle, or circle-dot) and 12 brightness settings (10 daylight / 2 night vision compatible).
Features include Solar Failsafe, Shake Awake, and a side-mounted CR2032 battery tray for battery changes without removing the optic from the mount.