DureFlex is a smooth inner-wall, flexible stainless steel chimney liner manufactured by the DuraVent Group. With its start in 1956 in Redwood City, California, Duravent is the preview company of the venting industry. They offer innovative, safe, and professional products for the HVAC and Hearth markets. In 1959, Duravent added DuraChimney to its product line offering wood chimney systems. The company continued to grow and in 1982, they were purchased by Simpson Manufacturing moving their California manufacturing to Vacaville, California and a manufacturing center was added in Vicksburg, Mississippi. In 1992, they again expanded adding the PelletVent product line that is now the highest recommended venting system for pellet stoves on the market. Propelled by innovation and the desire to provide the highest quality venting products, Simpson Manufacturing was acquired by M&G Group in 2010. The M&G Group is headquartered in the Netherlands and produces a wide range of flue and vent products in aluminum, stainless steel, and plastic. In 2013, Duravent consolidated its manufacturing facilities on the east coast, relocating to Albany, New York.