This is a Hobbywing part #86080080, 5V Black B Cooling Fan. 10000rpm @ 5V. High Performance Cooling Fan 3010

EZRUN MAX10
EZRUN MAX10-SCT

• Size: 30mm (L) * 30mm (W) * 10mm (H)Weight: 8.2g
• RPM: 10,000 @ 5V