UltimateONE offers the latest technologies in factory-built chimney design, providing superior performance, durability, and safety. UltimateONE’s inner liner and outer casting are constructed of all-welded 304 stainless steel for superior strength and corrosion resistance. Engineered with a web coupler design using an inch of Superwool insulation that makes contact at the seam, UltimateONE allows for pipe expansion and eliminates cold-air infiltration. Because UltimateONE is locked together with a latch-type locking band, no-tool installations are quick, solid, and secure every time.