Gasketed Coupler, Duct Fitting Diameter 18 in, Duct Fitting Length 42 in, Width 18 in, Duct Fitting Material Galvanized Steel, 24 ga Gauge, Gasketed Coupler, Height 18, Coating Galvanized, W. G. (30 in Positive / 30 in Negitive), Standards SMACNA, Self Sealing, No Fasteners Required, Reusable, Double-Bolt Design, For Use With Round Duct, Light Gauge Tubing or Hoses