These Subwoofer Boxes are made with pride in our own facility here at HiFiSoundConnection. They are constructed with the highest quality MDF that meets our rigid standards. Unlike our competitors, we do not use pressed cardboard or rice wood materials from overseas. All of these sub boxes feature high grade spring loaded terminal cup(s) for the absolute best connection's possible. All of the custom series enclosures are made to fit precisely into your vehicle to the get the maximum performance from every extra inch of wasted space.