ButtKicker has been making tactile transducers (shakers) for several years now. These are devices that make your chair, couch, or floor vibrate when low frequency material is playing. They were always very powerful, and in fact, more intense than many consumers wanted. You could always just turn down the volume, but then, you were paying for high power shaking that you were not using. So, ButtKicker decided to produce a shaker that is smaller, with less maximum shaking potential, and include a smaller amplifier. The BK-KIT-4 is the result.