This is the Hobbywing EZRun 18A Sensorless Brushless ESC.

Features:

Specifications:
Output: Continuous 18A, burst 50A.
Input: 4-9 cells NiMH/NiCd or 2-3S LiPo.
BEC: 6V/1A (Linear mode built-in BEC).
Resistance: 0.01 Ohm.
Motor Supported: Sensorless Brushless Motor.
Suitable Motor:

Suitable Car: 1/18 on-road sport.
Cooling Fan: Not included.
Size: 31.5mm(L) * 27.5mm(W) * 15mm(H).
Weight: 19g (Without wires)