Replacement gearbox for Sicma Finish Mowers . This is a new replacement aftermarket gearbox, at a price you can afford compared to a new OEM gearbox! Fits GM30 Series Finish Mowers in 48", 60" and 72" cutting widths. Does not fit the GM35-84 84" cut mower. Specifications: 1-3/8" X 6 Spline Input Shaft 1:2.82 Speed Up Ratio 4 Bolt Mounting 4-3/4" on Center.