7 mechanical parts, namely, differentials for use in lawn mowers, snow blowers, tillers, and other lawn and garden machinery, namely, plows, [ powered wheelbarrows, edgers, pavement cutters,] trenchers, [ stump grinders, vacuum blowers,] aerators, sweepers, snow throwers, fertilizer spreaders, brush cutters, roto-tillers, garden and lawn tractors, and commercial mowers