Motorised damper 1.Material: galvanised steel 2.Insulation outside 3.Size:dia 150,200,250,300,350,400,450mm 4.Lowest price Mottorised damper ,air condition parts,damperDuct installationMaterial :Galvanised steel 0.6mm or 0.8mm as required,but cost penaltyThere is one damper inside the body to stop the air in the duct go through or not5mm thickness insulation stick on the body to stop the air ...