1.High entire pressure 2.Big wind,low noise 3.Low ... close, windproof, rainproof and dustproof.5Newly punch forming fan blade, reasonable angel and reach the max. air flow ... process: noise test, vibration test .concentric performance test, fan blade turning speed test, input air teat and vehicle ... belt,fall the belt. Design by computer make fan blade forming more reasonable,high robustness,wind rate big ...