Rockboard 80 boards have a dimension of 24"x 48" x 2" inches and are manufactured by Roxul. Order Single Pieces on this page.
Roxul 80 is rigid mineral wool board with a density of 8 pounds per cubic foot. These boards are a great option for acoustic projects that require a rigid material.
If you need 4 or more pieces, order Roxul Rockboard 80 Case of 4 here.
For more detailed information, see Selecting the Right Acoustic Material for a comparison of these materials.