The 12.87 Inch Cummins Diesel Oxidation Catalysts with a 12.99 Inch Diameter are a highly durable and effective solution for reducing exhaust emissions. Made with stainless steel construction and manufactured according to OE technology, these catalysts offer a direct OE replacement for Mack and Volvo makes and models. With features like reduced backpressure and fuel consumption, as well as clamps and gaskets included, these catalysts provide high performance and practicality. Meeting EPA 10 exhaust emission norms, they are designed to match OE performance. Direct OE replacement numbers include 21212407, 21756506, 21212405, 21756505, and OTR82018.