Rockwool safe n' sound fire and soundproofing insulation. Just opened last week and used 5 piece of the 12 pieces. 7 pieces left in package. Stored inside. That's 58% left of the bag that I paid $92 for. 16" on centre 2x4 wood studs. Selling for only $25 which is less than half of what it's worth. Pickup in West Port Alberni.