Forward and Reverse Gear Box Transmission Kit for 3hp to 8hp Engines. Fits for Hammerhead and Trailmaster Go Karts with Reverse and many other applications. 16mm Shaft with a 5mm Keyway. 12 Tooth Sprocket for 35 Chain and a 10 Tooth Sprocket for 40, 41 and 420 Chain. Gearbox Positions: Forward, Reverse, Neutral. Forward Gear Ratio: 1:1:3 - Reverse Gear Ratio 1:2:6 ... Kit Includes: The Shifter Control, Shifter Disc, Shifter Cables, (2) Mounting Plates, 10 and 12 Tooth Sprockets, Shifter Assembly, 5mm Key and Hardware. Weight: 9 lbs.