The Hobbywing XRotor 1306 features a rotor with a special strengthened beam which guarantees super impact resistance, neat windings that help to produce low internal resistance and a six-bladed centrifugal fan greatly reduces the operating temperature of the motor. Special 240? heat-resistant windings, Super thin (0.2mm) silicon sheets, quality bearings imported from Japan and N54 super magnets guarantee high torque output. Hobbywing XRotor 1306 4500KV Titanium V1 Dual Pack Features: Super thin disc-type structure with a low centre of gravity guarantees better control feel N54 super magnets guarantee high torque output One-piece six-bladed centrifugal fan greatly reduces the operating temperature of the motor Dedicated 4mm bearings (the thickness is enlarged by 33% comparing to the regular 3mm bearings on the market) Spec Check: Brushed/Brushless: Brushless Sensored/Sensorless: Sensorless KV Rating: 4500 LiPo Cells: 4S No-load Current(A/10V): 1.1 O.D.(mm): 18 Length (mm): 15 Shaft Diameter (mm): 5.0 Weight (g): 13 (HW30405306)