1.700mm Roof Ventilator 2.ISO 9001:2008 3.Vertical Vanes 4.Larger exhuast capacity 5.Aluminum alloy anodic oxidation SKYAXIS 700mm natural Ventilator, firstly promoted by ... Use Quantity and less holes on roof, Saving Cost, Varipitch Design, Easy Installation, No Maintanance, Good Anti- corrosion, Longer Service Life. Skyaxis 700mm roof ventilator