This is an optional SSD RC TRX4 Overdrive Axle Gear Set, intended for use with all Traxxas TRX-4 models. This gear set provides an overdrive gear ratio from the ring and pinion gears, rather than the portal box. 

• CNC Machined
• Hardened steel
• 12T/33T overdrive ratio
• Fit stock TRX-4 locker/diff and bearings
• Direct fit in Traxxas TRX-4 axle

• 33T Ring gear
• 12T Pinion gear shaft