The Dana Spicer 10081578 is a pinion oil seal. A seal like this keeps lubricant inside the housing and keeps dirt and moisture out at the point where a rotating shaft passes through it, which protects the gears and bearings it guards. It is sold as an individual unit (each). A genuine Dana Spicer part from Pro Gear and Transmission. Pinion seals are size and application specific, so call us to confirm proper fit for your axle before you order.FeaturesDana Spicer pinion oil sealKeeps lubricant in and dirt and moisture out around a rotating shaftSold as an individual unit (each)