Perko Telescoping All-Around Boat Navigation Light Base Combo This Perko Telescoping Boat Navigation Light Base Combo features a clear fresnel globe that allows for all round visibility even when the globe orientation isnt horizontally aligned. With a locking collar on the pole, this design also provides limited cockpit illumination. Certified for use on power driven vessels under 20 meters 65.6 ft. in length and featuring a chrome plated zinc alloy base, this boat navigation light and base co