A special precompressed modified asphalt impregnated expanding foam sealing tape automatically makes a permanent elastic watertight seal to the existing drain, eliminating water backup. The flange and outlet tube are available in stainless, aluminum, PVC, or high temperature ABS. The drain is completely installed on the roof top with NO special tools and all hardware is stainless steel.The unit is available with either plastic or cast aluminum dome strainer and the outlet tube gives minimum downsizing to the existing drain. The Portals Plus ReRoof Drain makes a perfect roofing termination pointand offers an excellent connection to the plumbing below.