Mike Penland teamed up with HMF to produce “The most winning utility ATV muffler on the planet,” the Penland Pro Series. This is the premier exhaust for the utility rider/racer looking for maximum power, durability, and appearance. Exclusinve to the Penland Pro Series, the torque range modifier broadens the torque range, allowing better hook-up in rough terrain. And with the best muffler packing in the industry, you can spend more time riding and less time repacking.