Belva 12-inch Car Subwoofer Box Sealed 3/4-inch MDF Prelined Polyfil [MDFS1215] High Quality MDF Construction has better density and consistency to always sound great Polyfill allows your box to appear bigger to the subs which will then produce better audio quality Gold post terminals for clean and easy wiring access Box Dimensions: 16"L x 17"D x 13-1/2"H Seams are fully caulked for better efficiency