Filoform duct seals type MD are based on a specially formulated two-component expanding polyurethane resin. The polyurethane sealant is packed in a transparent plastic bag with a screw ring. In this plastic bag, the two components are separated by a clamping profile. After removal of the clamping profile, the two components are simply mixed together for 30 seconds. The package is now ready for use and can be easily opened with the use of the screw nipple. After pouring the resin in the duct, the resin starts expanding by forming CO². During the expansion the polyurethane filling material penetrates all areas inside the duct, thus sealing all openings regardless of the shape of the duct or borehole. After this the hardening process starts. The Filoform two component filler provides not only a 100% gas and watertight seal but also offers excellent mechanical strength.