When we bought our trailer in 2007 the dealer suggested the MaxxAir covers for the vent lids. We thought just an add-on sale to make more profit.
It turned out to be one of the best buys we have made.
The siding on the trailer has numerous hail dents
from sitting outside for the last 11 years, but no broken vent lids from hail. And.. the only damage to the MaxxAir covers is the MaxxAir labels are about worn off.