Model Max Efficiency Current (A) Max Load Current (A/60S) Kv (Rpm/V) Weight (g) Dimension (mm) Shaft Diameter (mm) Voltage Range (V) No Load Current (A) B20-40-10 21 28 4910 68 20*40 5 6~10.8 1.7 B20-40-20 16 20 3540 68 20*40 5 6~10.8 1.2 B20-40-30 10 13 2100 68 20*40 5 6~12 0.6