... steel 3.have a discount 4.ISO19001,14001 duct expansion joints ,expansion pipe joint ,air duct joint 1.Scope of Aplication: 2.Material ... A3inner sleeve1 set5Q235 A3outer sleeve1 set6Natural rubber ,sythetic rubberseal ring1 piece 3.Technical Performance of the product: 4.dimension: 5.Characteristics ... can also be fabricated in terms of customer designs.duct expansion joints ,expansion pipe joint ,air ...