This Dycem anti-slip patch is sewn onto the pipe bag cover to help keep the pipe bag up under your arm while playing. This can be extremely important depending on what type of material your jacket is made of. Some pipers use one patch where it is situated closest to the body and others like to put two patches on the pipe bag cover with the other being situated under the arm that goes around the bag. The patch is easy to install on to existing covers, or you can have one sewn on to your new bagpipe cover.