Pet Doors have always used pile brush material, magnets, and multiple flaps to create a seal. But this just slows down air leakage. Air leakage is what raises your energy bill, allows moisture and debris to enter, and bugs to come inside. Freedom Pet Pass M.E.S.S.A. sealing technology is a new way for pet flaps to seal. The Magnetically Engineered Self Sealing Application (M.E.S.S.A.) is a patent-pending magnetic formula that creates a magnetic circuit that produces a perfect airtight seal. Think of the circuit in terms of how electricity flows to create energy. When this technology is applied to Freedom Pet Pass pet doors take comfort in knowing the only thing passing through your pet flap is... your pet. Watch the short video to see how this works.