8 Pack - Acoustic Foam Corner Blocks 4" x 4" x 24" Finish Corners in Studios or Home Theater 8 Pack 4" x 4" x 24" Corner Blocks (charcoal only, 8 pack only) 16 Lineal Ft Finish off your 2",3",4" acoustically treated walls for an ultra clean look and added sound absorption Passes MVSS-302 Flame Tests (ultra-slow burning) High 1.07 NRC Rating - Absorbs Lows, Mid-Bass, Mid freq's