Click here for a dimension chart	Align BL Series BL430XL 3700 BL420LF 3200 BL430L 3550 Kv (rpm/V) 3700 3200 3550 Max Power (W) 350W 290W 300W Max Amp (15sec) 35A 26A 28A Max Efficiency 88% 80% 85% Io (No load A) Rm (Resistance) Shaft Diameter 3.17mm 3.17mm 3.17mm Gearbox N/A N/A N/A Motor Diameter 28mm 28mm 28mm Motor Length 39.8mm 35.6mm 35.6mm Motor Weight 70g 66g 67g Built in Fan N/A N/A N/A Max Rpm 25,000 25,000 25,000 Poles 6 6 6 Case Smooth Smooth Smooth ESC Timing 5-18 deg 5-18 deg 5-18 deg ESC Switching Freq. 16-22KHz 16-22KHz 16-22KHz