California Prop 65 Warning These items are found to have compounds and chemicals known to the State of California to cause cancer, birth defects, and reproductive harm. 1320 Performance Stainless Steel Headers are made of thick T-304 Stainless Steel and are mandrel-bent to form Tig welded for extra durability and fit your particular application with the best performance results possible while the thick flanges and strong Tig welds prevent cracking and offer long-lasting durability.