Turtle Wax Ice in the liquid bottle form. Can be applied on anything (gelcoat, plastic, glass, rubber moldings...everything). Can be applied in sunlight. Has great UV performance (my own personal .02). This is the ONLY stuff that I found worked on my boats in regard to not being immediately stripped off by hard water.
The only downside (if you consider it that) is if you want the ultimate in shine you'll need to go back behind & hit it with another clean mircofiber towel after you wipe the applied stuff off with another rag.