The Traxxas Slash RC short course truck roars into new territory with the On-Board Audio System! With the touch of a button and the flick of a switch, the sound of a 900+ horsepower engine revs to life. Powerful and loud, you will hear and feel the thunder and speed of short course racing! Supercharge your driving fun with this intuitive sound, sampled from actual Traxxas team trucks, featuring authentic gear shifting and engine revving mode. The Traxxas On-Board Audio System is rugged and waterproof for the thrill of all-weather driving. The adjustable volume lets you control the sound—think of it as the option to run mufflers or open headers. Go full-throttle and race with a friend, and push the scale-realism to a whole new level.