Pair of Tractor/Trailer Air Valve Knobs Made from Aluminum Interior Accessories Air Brake Knobs Compatible with Kenworth T680 Peterbilt 379 389 579 Freightliner, Chrome Stainless Steel (2 Set) TRUCK DRIVERFeature: This air val ve knobs for semi trucks with knobs,Please note this does not apply to trucks with pin style Fitment: Compatible with Peterbilt 379 389 579 Kenworth T680 Freightliner Western Star and other various trucks Durable: Our factory makes Knobs from metals of higher quality than those on the market, so it has the advantages of stronger hardness, better oxidation resistance, more durable Easy to install: Simply remove the parts that need