The Pro Series Laminar Flow mufflers bring the latest in performance and sound control technology to the street and racetrack. These round-cased mufflers deliver groundbreaking sound control while maximizing power and system efficiency. Pro Series muflers have a smoother, less raspy tone compared to the popular chambered style mufflers. The Pro Series will have a moderate exterior sound level with minimal interior drone on most applications. The laminar flow intrnal core helps speed up the exhaust pulses as they travel through the muffler, resulting in better throttle responce and more power throughout the RPM range. The full-size Pro Series mufflers sound great on gasoline, diesel truck or racing applications. The Pro Series shorty mufflers are a terrific choice for muscle cars and other performance vehicles with limited space and great sound is desired.