... Fans has been developed, Which is better than other factories in china and got good reputation from our customers. All of ... be adjusted according to the stack length.(3)Insulation class: B, F, H, our usaual is B class(4)protection class: IP42, IP44, IP54(5) ... CCC,ISO(10) Illustration of Model YWF-68L15P41.YWF: Asynchronous external rotor motor2. 68: Motor air gap diameter3: L15: Core length code4 ...