Volvo Penta SX-M, 6 And 8 Cylinder 1.51 / 1.79 Ratio Lower Gear Unit Single Propeller. Pressure and vaccum tested after new seals installed. Bearings and gears are in excellent condition some have been replaced. Shafts are straight. Functions beautifully. Has O ring seal seat in the lower gear unit. Fits SX, SX-M and others.