To protect the costly investment of your piping or ductwork system , and significantly extend its service life, specify FlexClad-400 sealing system from MFM Building Products. FlexClad-400 is a patented, water and weather-resistant, pre-fabricated, self-adhering, sheet-type protective membrane. The top surface is UV-resistant embossed aluminum that reflects heat and can aid in reducing energy costs. It is bonded to extremely tough, high-density polyethylene reinforcement material that is backed by a layer of aggressive, rubberized asphalt.