Force II™ Aluminized Steel Cat-Back Exhaust System with Single Side Exit (17362) by Flowmaster®. Exhaust System Type: Cat-Back. Exhaust Tubing Material: Aluminized Steel. Main Tubing Diameter: 3". Exhaust System Sound: Mild / Stock. The Force II Series is designed for a reach deep tone experience, suitable for everyday street driving. The character of the exhaust sound still has the deep, rumbling tone that signifies power, but at a more subdued decibel level that gives a pleasant performance character to driving without being tiring.