This listing is for a clean Ford Sterling 10.50" 3.73 ratio ring and pinion. These parts were removed in perfect working condition and were replaced with 4.10 gears for improved performance. These parts will fit any Ford 10.50" rear axle found in all 1999-2016 F250 F350 and Excursion 2 or 4 wheel drive. The 3.73 ratio will offer more fuel savings than most 3.55 gears included in this axle from the factory. They can also make great inexpensive repair parts a reliable spare set for the heavy off-roader or chase truck. Don't miss out on genuine Ford Motocraft quality at this low price. Thanks for looking!