... of different materials, take 500 model as examplematerialWeight of turbine headperformancelife-spanColor steel plate4.0-5.5 kgRust easily, ... retardant resistance, nylon bracket,rivet connect.Advantageslight dead weight,fast speed of rotation,stronger preservation,high efficient exhaust ,solidity,clean, ... 35 0ºC,the ventilator begins to rotate when wind speed outside is 0.12m/s.Roofing anglefrom 0 - 22 ...