Earthquake Sound Corporation is the original inventor of the Shallow Woofer System (SWS) that produces a lot of bass from a small space. They are a popular choice for replacing OEM car speakers with shallow mounting depths. In addition to OEM applications, the SWS series are the perfect bass solution for any car. Many factories are now using woofers in small areas. To improve your bass, simply replace the factory speakers with the SWS woofers no need for extensive modifications to accommodate large subwoofers.