So here is my question , I'm getting ready to install my trav'ler on the roof. The video that I've seen shows putting a "silicone" down before screwing trav'ler down. What is this product ? Then what do you put over all the screws when you are done ? Thanks Jeremy

Also I have some places I want to reseal around a/c unit, what is process for that , some kind of cleaner ? then some type of sealant ?