My truck got semi-gloss black under the fenders
then sprayed with a full coat of 3-M rubberized
undercoating.(lg. spray can) Then in 30 days I give
it another heavier coat...The cab got undercoating that comes in a 5 gal. pail, brushed on using a
6 inch brush...Not only does it protect the fenders
from pecks, it offers much sound-proofing...BB