Bleached, 100% cotton cheesecloth with a 20x12 thread count. This product is qualified to Aerospace Material Specifications 3819 A&B, Class 1 grade, as well as many industrial-specific specifications including: Lockheed Martin P5396-1(A). Douglas Material Specifications 1820, Boeing Material Specifications 15-5F, L-3/Raytheon Part No. 2012. Put-up in a precut roll. Each roll has 128 pieces. Each piece is 9"x24" folded and 36"x24" when opened. One roll per case. Sold by the case.