I have repeatedly seen trailers boat and PWC trailers equipped with mostly Optronics rear lamps fail on the road. Just last weekend I'm following a trailered Seadoo and the left rear lamp is blinking intermittently. A friend had the same problem as were loading his SeaDoos onto his trailer and I took a harder look only to find that 1. the sockets to the lamps had rotted and 2. there are voids throughout the housing that allow water to seep in!! I must be missing something because this is a routine install on new trailers but it would appear that sealed lamps would be the better option! If I'm missing something, please fire away; if not, when you go to buy a watercraft trailer, it might be a good idea to insist on sealed incandescent or LED lamps.