Auralex Acoustics 2PYR24CHA Studiofoam Pyramid Acoustic Absorption Foam, 2" x 24" x 48", 12-Panels, Charcoal Pyramid cut offers superior sound absorption and an aesthetic look Effectively reduce standing waves and flutter echoes Won't crumble with age Absorbs up to 60% better than other brands with an NRC of .70 Class B Fire Rated