Used 1987 Mercury 9.9 hp 2 stroke twin cylinder lower leg gear set. Forward gear part number 0043-41371A1 with 27 teeth and 6 cogs. Pinion Gear has part number 0043-420411 with 13 teeth and 10 centre spline. Reverse Gear part number is 0043-44115 and has 27 teeth and 6 cogs. Part numbers are per online manuals. All of these gears were removed from the same lower leg assembly. This outboard motor had serial number 0A719610 and was assembled in USA. Similar models had serial number range of 0A197112 to 0D280999. Callipers are not included but only shown for dimensions. Since these parts are more than 10 years old we suggest to change gaskets and seals. To avoid injury, harm or malfunction we suggest that all our parts be installed by a certified outboard motor mechanic. We only ship to Canada & USA.