The patches are 100 % cotton kitted fabric. They are lint free, they will not shed or fray and have no loose strings or threads to get left behind. Because of the knit in the fabric, it grabs fouling easily therefore cleaning much better than flannel or acrylic. The 6 x 6 patches are a premium k270nitted pique fabric.  Suggested sizes are:  1-1/2" patches use for .22 rifle up to .270;  2-1/2" patches use for .338 to .357; 3" patches use for shotgun sizes; 6" patches are for 37-40mm.