Knauf "3.0#, Black Acoustical Board" that's never been installed. To the best of my knowledge, this material has no R-Value (heat/cold insulative value), but is intended as sound insulation. If you're building a studio, now's your chance. The only retail outlet I could find a price for this material was amazon, where pack of six 2' x 4' pieces sells for $160. That the coverage equivalent of 1 1/2 pieces of this material.