For boats under 23' length without electrical systems, these battery-powered navigation lights offer the advantages of LED brightness and extreme reliability. Navigation lights are rated for speeds up to 7 knots, and are watertight and buoyant, in case they are knocked loose. Powered by four AA batteries (sold separately), with ON-OFF pushbutton switch. Light comes with a glue-on PVC inflatable mount (with the light removable using a quick-pin). Light housings are 2-1/2"dia. x 6-1/2"L.