... be installed on ships,boats,barges,watercraft,dredger,work boat,vessel,river boat,towage,warship SPECIFICATION 1).Nominal night visibility:2km-5 ... .5km 2)Turn on at dust and turn off at dawn ... management. 4)Waterproof and shock resistant 5)Nearly recharge themselves at nearly all kinds of conditions. 6)Automony time:steady on ...