The Metal-Fab Corr/Guard catalog features 3”, 4” and 5” diameters both in single- and double-wall configurations. The new vent has special snap-lock tabs that click into locked position when the pipe is pushed together. No tools are needed. A special “gold seal” gasket is molded rather than extruded. Precision tolerances provide a water-tight fit and prevent sagging on long horizontal runs. The flue is constructed of superferritic stainless steel, and Corr/Guard is tested and labeled to UL1738 for Category II, III and IV gas-burning appliances.