Reasonable cone designing , low noise ,big air flow, strong ventilation , low operation cost;Imported bearing, high-strength , low noise, durable Using air downstream principle ,PVC shutter or aluminum shutter, antioxidant, light weight, no distortion , open and close sweetly ,prevent backflow of air High-strength more high-gluten strength aluminum-magnesium alloy wheel, light weight , high strength ,toughness good6 pieces stainless steel blades, no distortion ,no breaking ,aesthetic durability There are two types of fan house ,slant wall type ,upright wall type ,could satisfy varieties need of different customersThe high efficient and energy-saving motor passed the national CCC certification .Also protection class: IP55 , insulation class: F grade