These headers are specifically designed for the Porsche 906. They have been very popular for actual 906 Porsche's or 906 type re-creations. Our headers are made in the USA from equal length, mandrel bent 16 gauge mild steel with a primary tube outside diameter of 1 5/8" and an inside tube diameter of 38MM. Headers are sold in pairs only and come with all gaskets and fasteners needed. Ceramic Coating is also available (See website)!