Original Factory gear for Ford 10.25" in a 3.55 ratio. for long yoke, '93 and newer. OEM gears are recommended for quiet applications where noise may be an issue. Factory gears are the quietest application available on the market and often come at a higher cost. Factory gears come with a one year warranty against defects. When installing this gear set in a 99 & newer 10.5" housing you will need a 10.25" bearing kit.