Use this Delta Delta ASB02505SHA-AY6B as a great little fan (25x25x10mm) for your 3D Printer and a recommended fan also for the Xol-toolhead, considered to be one of the best you can get.

Specs:

Current: DC

Voltage: 5V

Airflow: 4.3 CFM

Noise: 31 DBA

Speed: 15000 RPM