This single 15" ported subwoofer enclosure is made from high-quality 3/4" USA MDF and features a platinum spring loaded terminal for optimal performance. The air volume is 3.36 cu ft and the port area is 46 sq inches. The enclosure is 100% American-made and environmentally friendly. The hole diameter is 13 7/8 inches, the width is 31 1/4 inches, the height is 18 1/4 inches, and the depth is 15 1/2 inches.