Electrical insulation compound - GIF

[nova_robotics]

I use this stuff AFTER I've put on a wire nut or similar to provide sealing to the connection from water/dirt/humidity. In particular, trailer tail lights. I hook the light connections with wire nuts, and then seal them with this stuff

Wire nuts for vehicle chassis wiring is the second sketchiest thing I've read in this thread. Wire nuts do not belong on a vehicle, especially underneath them.