Model B28-48-10 B28-48-20 B28-48-30 Max efficiency 35 28 24 current(A) Max load 40 34 30 current(A/60s) Kv(RPM/v) 3900 2560 2060 weight(g) 140 140 140 Dimension(mm) 28*48 28*48 28*48 Shaft diameter(mm) 4 4 4 Voltage range(V) 7.2-12 7.2-12 7.2-14.4 No load current 1.6 1.3 0.9