We are the exclusive United States supplier of quality firestop and weatherseal products for multi-cable and cable tray penetrations. From our headquarters in Melrose, Massachusetts, CSD#s team of experienced firestop professionals offers complete design, specification and sales service. A division of Dorn Equipment Corporation, CSD Sealing Systems has been in the firestop business since 1986 and has built an outstanding reputation for meeting customers# need with quality products delivered on time. CSD Sealing Systems is a registered ISO 9002 compliant company. \r\n\r\nOur products are U.L. classified and have been used in all types of industries around the world. \r\n