2" x 12" x 12" Charcoal Acoustic Pyramid Studio Foam 12 Pack by DeluxeFoam Pack of 12. Covers 12 sq. ft. Effective against standing waves and flutter echoes in most small-to-medium sized rooms. For use in vocal booths, control rooms and studios. Overall NRC: 0.45 Functions as a full frequency bandwidth absorber for any size room when used in conjunction with corner bass absorbers and male/female broadband absorbers.