SEI SE228 Mercury 3.0L V6 Counter-Rotating Lower Unit 1.75:1The SEI SE228 is an aftermarket counter-rotating replacement lower unit for select Mercury 3.0L V6 two-stroke outboards rated from 200300 HP. Designed for standard Fleet Master gearcase applications, it features a 1.75:1 gear ratio and is available with a 25″ or 30″ driveshaft.This item is subject to a 20% restocking fee.Year, serial number, and horsepower are required to process your order. Please contact us with this information after placing your order. Processing will be delayed until this information is received.FeaturesCounter-rotating lower unit for compatible port-side applications1.75:1 gear ratio25″ or 30″ driveshaft options13-spline driveshaft and 15-spline propeller shaft4.88″ torpedo diameterFitmentFor select Mercury 3.0L V6 two-stroke, 200300 HP outboards using a counter-rotating standard Fleet Master gearcase. Confirm your existing gearcase type, rotation, ratio, shaft length, and spline configuration before ordering.Does not replace Torque Master, Torque Master 2, or Sport Master gearcases.OEM Replacement References25″ SEI 90-228-A25: Replaces 1600-880686A52 and 1600-880686T38.30″ SEI 90-228-A30: Replaces 1600-880686A53 and 1600-880686T39.