This splined drive adapter meshes with prop shaft to transfer torque to the propeller. Required for installation of Michigan Wheel Vortex and Apollo propellers. For use with Evinrude/Johnson Outboards, 3-3/8" Gearcase, 40-75 HP; Nissan/Tohatsu Outboards, 3-1/4" Gearcase, 50-70 HP; Suzuki Outboards, 3-1/4" Gearcase, 35-65 HP. For use with Honda/Nissan/Tohatsu/Mercury | Drive Adapter For Evinrude/Johnson/Nissan/Tohatsu Outboards