Metallic substrate spun catalytic converters, OBDII & 49 state compliant. Full stainless steel construction. Metallic substrate offers higher flow and lighter weight. Uses advanced spiral wound ultra thin foil. Includes our custom made soft crush graphite collector gaskets for a leak free seal. These are made specifically for the new HR motor by BERK. Made with pride in the USA. As of January 1st, 2009, performance high flow cats are intended for off-road use only in the state of California.