The DuraGrip guitar picks are made from D'Addario Duralin (also known as Acetyl or Delrin) is a unique material with an extraordinary combination of strength, stiffness, dimensional stability, fatigue resistance and low friction. Unlike other standard delrin picks, DuraGrip features a unique, stamped checkerboard surface that gives superior grip while playing. Duralin picks are known for their bright clicking sound when hitting strings and are preferred by many soloists for their clear articulation on fast single note passages.