Hobbywing made FAN-2008SH-5V-15000RPM@5V-0.135A-BLACK 30860500 (HW-30860500) Cooling Fans Motor / ESC / Cooling Fan
Using this type of fan mounted on your ESC heatsink, then you will have the optimum cooling performance.
Specifications: Oil/Porous Bearing/Non-waterproof/JR-3P Male Plug/L=35mm
Applications: XERUN XR10 STOCK SPEC