This is the Tekin Pro4 4300kv Heavy-Duty Brushless 550 Motor 5mm shaft. The all brand-new Tekin Pro4 Heavy-Duty Motor raises the bar in offroad power. Features: CNC Machined 6061 T6 Billet Aluminum Heatsink Can Rebuildable Design Precision Engineered for Optimum Energy Conversion High RPM ABEC5 Oversized Bearings 4 Pole 12 Slot Hi-torque 550 Motor Design Neodymium Sintered Magnets High Purity Copper Windings Optimizes Efficiency Dual-Plug Sensor Wire Harness for usage with all sensored systems The Pro4 HD's 4 pole design and longer 550 can offer performance gains across the board and off the charts when as compared to basic 1/10 scale motors. Tekin's Pro4 HD Motor has the power and torque to level the competition. Created for usage with 2S-4S power systems 1/10 scale 4WD Brief Course has never had this type of power! Combine the Tekin Pro4 HD Motor with a Tekin RX8 ESC in your 4WD Brief Course and hold on!