After the individual metal sections for the tubular exhaust header project are cut and prepped, builders move to STAGE III: Assembly and Welding. STAGE III utilizes one of the most innovative products to hit the fabrication industry in decades: the patented icengineworksTM stainless steel tack-welding clamps. These clamps provide an amazingly quick and exact way to firmly hold multi-sectional tubular assemblies together Proper relative rotation at each joint is easily and minutely adjusted until the entire assembly becomes a solid and faithful recreation of the original plastic block model. They provide safe and endless opportunities to verify fitment for clearance, accuracy and exact alignment with the receiving tube ends at the head flange, exhaust collector, or icengineworksTM Collector Dummy before tack-welding the assembly. Sold in sets of 4 and 8.