This is CNC Spiral Cut Diff Ring Gear for the 4XS.
This is a direct replacement with the original Straight cut gear.
Precisionly made Spiral Cut Gears ensure the smoothest of the ride and maxmimum performance from the transmission.
This is a MUST Option parts for the serious racers.
NOTE: YOU CANNOT USE THIS SPIRAL CUT GEAR WITH THE ORIGINAL STRAIGHT GEAR. ONLY WORKS WITH 15811 CNC INPUT PINION GEAR.