The flex agent is appropiate for anything that you want the finish to be
impervious to any abrasion or rock marks.
It's like coating the surface that is refinished in a rubber bag.
Yes it is primarily used for rubber bumpers.
I refinished the front end on my rock chipped Van with Dupont flex agent
mixed in the clear coat.
It has not rock chipped in 4 years so far.
It's causes the paint act much like, and similar to urethane Imron
(rubber based paint and very flexable and abrasive resistant)
I aso just refinished my power mirrors with the same formula.
They will never chip, fade, peel, crack or rock mark.
Actually I use flex agent in all my paint work.
This system works very well.

RC