... and close, windproof, rainproof and dustproof 5. Newly punch forming fan blade, reasonable angel and reach the max. Air flow, ... mini. Noise 6. Double bracing (E style) belt transporter, Europe industry motor standard 7. Safety net easily tear down 8. Strictly ... test process: Noise test, vibration test, concentric performance test, fan blade turning speed test, input air test and vehicle efficiency ...