Portals Plus has developed a unique Mechanically Expandable Rubber Seal, "The Premier Seal". The Drain is designed to replace existing drains in retrofit applications. All installation is conducted on the roof surface. The seal is activated by tightening the internal screws with the Premier Screwdriver. The Seal utilizes PVC flanges for increased strength and stainless steel screws to compress the EPDM rubber gasket. The compression of the seal expands it and makes contact into the existing piping of the pre-existing drain, therefore, preventing vertical movement and stopping water damage into the building. The Premier Seal exceeds SPRI and ANSI Retrofit Drains requirements.