Oni Tools Outdrive Coupler Alignment Tool is a direct replacement to OEM parts number 91-805475A1, 91-57797A3, 3851083 and 18-4442. Package includes one Engine Alignment Tool. Designed to fit for Alpha One, Pre Alpha, Gen 2, "R", Bravo, All Cobra Sterndrives, Volvo SX, All #1 Drives, 1, 1A, 1B, 1C. Our tool Will NOT work for Mercruiser TR and TRS Outdrives. Specifications of the tool are as followed 1.010" diameter, 2.200" long (section that fits into coupler), 1.150" diameter. 2.750" long, and 1.375"diameter rest of bar (section that fits gimbal bearing inside diameter). .The length of the Alignment bar is 23-5/8 inch. Oni Tools Will Help You Find the Right Marine Specialty Tools and Parts for your Boat Repair and Maintenance Needs. We Offer a Variety of Aftermarket and OEM Parts to Cover your Engine, Fuel System, Ignition, Intake, Propellers, Motors and More. When it comes to accessories, we have that covered too.