Frank is correct. That is good stuff.
Both of my TT's used a lot of exterior silicone. None of it ever separated from my fiberglass walls. It is extremely hard to remove when replacing parts like light fixtures and such. It also is unsightly when it ages.
Proper sealing materials are different for different uses. Roof, windows, electrical fixtures all have different needs. However, tube caulking is always an easy way to quickly seal a leak.
Dutchman Kodiak Cub KD176RD 2018
Nissan Pathfinder 2015