6 Inch Dura-Vent Duratech Anchor Plate. From its headquarters in Fairfield Iowa Chimney plays a major role in providing for the Chimney industry.M & G Duravent 6DT-AP 6 Inch Dura-Vent Duratech Anchor Plate Chimney has the privilege of serving over 80% of the chimney professionals in America.Founded by Robert Daniels "Sooty Bob " in 1978 Chimney has grown from a one-man operation to a national network of six warehouses and a manufacturing plant.