Davis RailLight Premium Solar Light with 4 LEDs Fully marinzed for use in salt or fresh water Fastsolar technology quickly charges internal battery Automatic on-off light sensor High-low-off waterproof switch built-in Comes with Quick Mount System for round or square rail mounting Waterproof marine-grade solar/LED light Fast Solar charging system optimized for all outdoor conditions Provides over 8 hours of light on a full charge