The Holosun HS407C-X3 builds on the proven 407C platform with a reinforced housing and updated brightness control system designed for shooters who need a carry or duty optic that manages itself without demanding attention. The forward-facing photodiode reads ambient light continuously and adjusts reticle intensity automatically, while Solar Failsafe backs the CR1632 battery with solar power in auto mode - keeping the dot at a usable brightness through changing conditions and providing a failsafe if the battery runs down. For situations where automatic control isn't preferred, manual brightness adjustment is available with memory mode, which returns the optic to the last-used setting on activation. Lockout mode prevents accidental brightness changes during carry or duty use, keeping the optic set exactly where it was left. The RMR footprint puts the HS407C-X3 on a wide range of pistols without adapters, and the low-profile housing keeps the optic close to the slide for a clean, snag-free carry package. Shake Awake ensures the dot is live the moment the gun moves, and the side-loading CR1632 tray allows battery replacement without removing the optic from the pistol. 2 MOA Dot, Red Trijicon RMR footprint for broad pistol compatibility Forward-facing photodiode automatically adjusts brightness as light changes Solar Failsafe provides continuous power backup in natural or artificial light Shake Awake with memory mode and lockout for carry and duty use Side-loading CR1632 battery with up to 100,000-hour runtime Hard-anodized 7075-T6 aluminum housing IP67 waterproof and 5000G vibration rated