The 2006 Hyundai Elantra GLS model typically has one catalytic converter. The catalytic converter is an emissions control device that helps reduce harmful pollutants in the vehicle's exhaust gases. It is usually located in the exhaust system, between the engine and the muffler. If you suspect an issue with your catalytic converter, such as reduced engine performance or increased emissions, it is important to have it inspected and potentially replaced by a qualified mechanic to ensure proper functioning of your vehicle and compliance with emissions regulations.