Features: You can adjust frequency. Just gently rotate button of the controller, and you can also control the sound with different frequencies, so that song sounds different, the heavy bass is deeping and it is very convenient to use. Installation is usually very simple, with detailed instructions, suitable for enthusiasts to modify, but also by professionals to install. Improve the bass of the sound system, so that car owners can enjoy a better music experience while driving and increase driving pleasure. Optimized your driving sound track during commutes, or daily errands while maintaining control over bass intensity from driver seat. Suitable for head units, home sound systems, and amplifiers requiring control. Specifications: Component:Plastic Size:Approx.5x4x3cm/1.97x1.57x1.18inch Package Includes: 1Pc Bass Controller note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.