Patented Gaffrig Performance Mufflers were designed specifically for high horsepower engines - Highly polished, all stainless steel construction with TIG welding. - Air actuated by pneumatic cylinder and pump. - Remote dash switch allows operator controlled opening and closing on automatic mufflers. - Available in 4", 4 1/2", and 5" diameter tail pipes. - Kit includes: air cylinders, air pump module, fittings, switch and hose. Powertip Silencers - Maximum noise reduction - Clamp-on mount to end of exhaust pipe. - Down firing exhaust when muffler baffle is closed - Measures 11" x size of pipe