... 3.Material:rubber,steel 4.12 years OEM producing experience air duct joint a:Section Drawings: 1,bolt 2,nut 3 ... ,gasket 4,inner race flange 5,corrugation pipe 6,dorsal plate flange 7,inner sleeve pipe ... and little counterforce to the brackets of pipeline. 2) shock absorption and noise decrese, heat and dust insulation 3) the displacement can ...