Heavy 47g Modular Brass Inner Knuckle Weight, for TRX-4Hot Racing heavy brass modular add on inner knuckle weight for the front of the Traxxas TRX 4 crawler equipped with the Hot Racing TRXF21HE Modular Brass Outer Portal Drive Housing. Adds weight to the Traxxas TRX 4 crawler where it needs it down low. Adds 47g per hub to lower the vehicle's center of gravity, increase its stability, improve climbing, reduce the chance for flipping backwards, and make it an overall more capable crawler. Features: CNC