Electronic Speed Controller (ESC) is a electronic circuit to vary the speed, direction and possible to act as a dynamic brake, of a Brusless Motor. This particular ESC is recommended with A2212 brushless motor (1000kv, 1400kv,2200kv). Specifications - Weight : 23g Dimensions: 45.0*24.0*9.0mm Current(A): 30-40 BEC : 3A PWM: N/A Li-Po : 2-3 Ni-Mh/Ni-cd : 4-10Ni-Mh Constant current : 30A Max 40A <10s Li-Poly 2-3 cells; Ni-MH 4-10 cells Auto Detect Break On/Off Auto Low battery Slow down at 3.0V/cell Lipo, cut-off at 2.9V/cell Lipo