An extremely tight weave 100% cotton fabric. The U.S. Government created a set of specifications which had to be adhered to by vendors who manufactured this material for the military (these patches match those mil specs). The tight weave 100% cotton fabric is rugged resists tearing and prevents burn-through. All patches are biodegradable and nontoxic. Uniform thickness of .015 assures consistent velocities from shot to shot. 100 patches per bag.