In spite of its name, this is not a navigation light. The Mega-Light Masthead model has an attached bracket for mounting in the cockpit, or on an RV or cabin.

This model features an integral light sensor that turns the light on automatically at dusk, and off at dawn. No switch is needed, but one can be added for manual control after dark.
It includes 12 wire leads for connection to a 12 volt system, and requires a user supplied 1 amp in-line fuse.

This energy efficient utility light uses approximately 1 amp-hour per night (just 0.11 amps at 12 volts).
It puts a very low drain on your boat, car or RV battery it can run continuously for over 2 weeks on a typical 50 amp hour car battery!

2-part combination lens a focused Fresnel lens for 2 mile visibility, and a flood lens for area or task lighting
100% waterproof O-ring seals lens to base
(2) easy to change light bulbs are included one bayonet type bulb draws just 0.11A and can be seen for up to two miles. The other bayonet bulb draws 0.32A and is more than twice as bright
Dimensions: 2" Dia. x 2-3/4"H