Set of 4 - Acoustic Foam Bass Trap Studio Soundproofing Corner Wall 12" x 12" x 12" Corner Wall Foam is used with Wall Panels to cover up the 4 corners of the room Good for studios, booths, theaters, schools, home, podcasts, professionals & hobbyists Professional, High Quality Durability and Effective Noise Reduction Coefficient: 1.32 nrc Made in USA by Mybecca / CA Technical Bulletin 117-2013 Flammability Standard Compliant