TIG welded and CNC manufactured by Moroso to eliminate distortion and ensure a prcise fit. Fabricated entirely from aluminum - ultra lightweight at less than 2 lbs each. One piece rigid gasket rail provides a precision-flat surface for superior sealing. Air-tight sealing allows the engine to pull greater vacuum for improved ring seal and power. Tall enough to clear all popular race combinations. Notched at each mounting location with socket-sized clearance for quick installation and removal.