... push-pull, open- close device Provide 7*24 hours on-line service.Technology parameters Fan specificationsBlade Diameter mmFan speed r / ... alloy, light weight, high strength, good tensile 3. Strap adjust automatically, no need manual adjustment during lifetime 4.Shutter ... , Yunnan, Liaoning, Hunan, Hebe, Jiangsu, Zhejiang, and so on, more than twenty provinces and cities, exported to Southeast Asia ...