FlowTech's unique precision engineered high performance header gaskets come in complete sets for your specific FlowTech header application! Each set contains one pair of header flange gaskets and at least one pair of collector gaskets to make reinstalling your FlowTech headers quick and easy. The gaskets are made of a P73 Ferroglass non-asbestos facing material mechanically secured to a perforated metal core. This non-organic combination gives you a great seal the first time, with a perforated metal core for support during installation and long after.