Header Collector Seal Kit. Flowtech Real-Seal header and collector gaskets are a revolutionary break through exhaust sealing technology. Constructed of separate layers of "dead soft" aluminum, Real-Seals provide do it once solution that will not burn or blow out. Real-Seal gaskets will work when an o-ringed gasket will not because the "dead soft" aluminum conforms to create a leak proof seal. Real-Seals can also be easily trimmed and you can use them over and over again.