This "European Racing Headers" Gasket kit includes all of the nuts, bolts and washers needed for a new installation of European Racing Headers or for those folks who want to "Freshen" up all of the gaskets and fasteners on their header system. Please specify primary pipe diameter when ordering (1 1/2" or 1 5/8" or 1 3/4"). This is the O.D. of the pipes that connect to the motor side of the headers.