Narva Model 37 12V LED Slimline Rear Stop/Tail, Direction Indicator Lamps-$65.50 Designed from the ground up, the Model 37 trailer lamp has been engineered for use on boat trailers where regular submersion is common. The lamps are protected from water ingress with a two-stage system that incorporates ultrasonic welding and a two-part epoxy glue. This allows the lamps to comply with the stringent IP68 standard.