Proflow's universal catalytic converters are made from high-quality stainless steel, have a 4" diameter honeycomb substrate core and feature a slip-fit design for easy installation. Their universal design allows them to be used with virtually any exhaust system. Whether you're building a custom exhaust or just need a replacement, Proflow's universal catalytic converters will enhance your vehicle's performance, while producing cleaner emissions. The units are available in a variety of size's.