Radicon David Brown AA730 14.5:1 Ratio Speed Reducer Gear Box Series ARatio: 14. 5: 1 Input RPM: 1750 Output RPM: 120. 69 Inputshaft diameter: 3 4" Output shaft diameter: 1 5 8" Female Vent Not included Approximate dimensions of main body not including bell shaped motor adaptor (If Included) Length: 13" Width: 7" Height: 10" All gearreducers must have a breather vent. This allows for expansion and contraction of the air within the casing as a result of temperature changes. If a gearbox is used without a breather, oil