All TS-W series subwoofers are designed to produce high-quality sound. They are equipped with a fully enclosed basket, which suppresses repulsion efficiently, ensuring accurate, clear and rhythmical bass. Each sub also comes with advanced technologies, such as a Pioneer patented IMPP composite cone, a rigid 3D-shaped cone design, and large double stacked magnets. On top of that, these TS-W series offer easy installation in many different cars. TS-W311D4 This subwoofer brings great flexibility thanks to its 4? dual voice coil, which allows you to opt for a 2? or 8? set-up (provided that there is correct power matching between the sub and your amp). The TS-W311D4 delivers up to 1400 Watts and is suitable for enclosed use.