A great way to route cables from the outside of a car roof. It is understood that you will use something under the panel and on screws not included to waterproof the contact between the plastic and the roof. My process was simple, run the wire through and decide how long it will be inside and out, then thread the device around the wires, drill a hole, run the wires through the roof, apply putty, where the box goes, knead and screw. Metal screws, then apply with putty the self-leveling materialโฆ