The Pyle PLQB8 8" 400 W Bandpass Enclosure System is specially designed for maximum slam. This woofer is mounted inside a dual-chambered box - one sealed, the other ported - with the sound waves emerging from the ported box. This yields a low, narrow frequency sound (35 Hz - 800 Hz) with a huge punch that's super efficient. The 400-W 8" subwoofer is built with a specially treated black rubber edge suspension, so the only vibrations you'll be hearing will come from your music. The blue polypropylene cones provide maximum boost and extend the life of your product and ensure the safety of your vehicle.