Hobbywing made FAN-3010BH-5V-10000RPM@5V-BLACK-A 86080150 (HW-86080150) Cooling Fans Motor / ESC / Cooling Fan
With this specific fan installed on your ESC heatsink, then you'll definitely have the maximum cooling performance.
Specifications: Ball Bearing / Non-waterproof / JR-3P Male Plug / L=200MM
Applications: regular applicaion. well suited for engine air-con