Down 4 Sound 320 Mill Sound Deadener 18 sqft Acoustic Foam 3 in 1 each sheet is 11 x 22 11 Sheets RillaMat 5XL the THICKEST Basshead Deadener in the World. Made from the highest quality components, Butyl Rubber, aluminum and Foam Before applying deadener, ensure the area is fully clean; we suggest using 80% rubbing alcohol. Once thoroughly cleaned and dry, apply sheet, and roll. If applying in cold weather under 60 degrees, use a heat gun to apply or warm the area. Watch out for airbag sensors and fastening holes for interior panels. Warning this product may cut you, use safety gloves. We are not responsible for any damages or cuts or applying errors.