Fit System custom fit towing mirrors snap over your vehicle's existing mirror to give you added vision while towing. Easy to install, no holes to drill. Fit System have engineered these OE fit snap-on mirrors to conform to the factory model and style. Will not block vision of your original mirror and can be folded away with the snap-on towing mirror on. Fits 1997-2002 Ford Expedition, Lincoln Navigator; 1997-2003 Ford F-150, F-250LD, 2004 F-150 Heritage.