Hobbywing item HW-30860200 - FAN-WP3510SH-5V-10500RPM@5V-BLACK-A 30860200 Cooling Fans Motor / ESC / Cooling Fan
Using this fan installed on your ESC heatsink, you'll have the most cooling performance.
Specifications: Oil/Porous Bearing / IP55 Standard / JR-3P Male Plug / L=70MM
Applications: EZRUN MAX6, QUICRUN-WP-8BL150