Auralex Acoustics Studiofoam Metro Acoustic Absorption Foam, 2" x 24" x 48", 12-Panels, Purple High density, open-celled acoustical foam. Absorbs mid/high frequency reflections to control the ambience of any room. Alleviates flutter echo and slap back. Will not deteriorate or crumble apart over time. Partially formulated out of soy components to reduce petroleum based chemical usage in an effort to curb deopendance on fossil fuels.