You have to the use of laying your skids on a complete bed of leveled gravel. Just what the potential of someone throwing rubbish or an aura condition outdoor unit falling (maybe out of bad installation or weather) and but in addition roof of one's car? https://Www.Slhsoccer.com/fr/externe/aHR0cHM6Ly9MYXVuY2hoYXBweS5jby9ndWlkZXMvY2hhbmdlLXdlYnNpdGUtdGFiLW5hbWU.html