APF-manufactures the most durable and wide-ranging inspection ports for the oil, gas and petrochemical industry. The acquisition of it's own elastomers molding facility has been instrumental in the development of matching inspection ports to process temperatures, from extreme heat to cryogenic applications. The Access Plug Flange ensures the integrity of the system, even if the insulation is lost or discarded during the inspection process. Our Access Plug Flanges are manufactured under patents owned by David D. Barton, President of APF Inc. \r\n