Nordfab 3260-0600-100900 Ducting Qf Clamp with Pin, 6" Dia, Galvanized Steel Clamps come standard from factory with Nitrile seals. Silicone or petrel seals are optional - specify when ordering. Clamps also may be ordered optionally without seals Galvanized clamp supplied with galvanized bridge pin's clamp supplied with SS bridge pin 3" to 6" Clamps: Small bridge pin with 3/8" wide seal from factory