Pick D'Addario Black Ice USA.

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. Normally used as a replacement for metal bushings and bearings in industrial applications, this extremely durable polymer is ideal for picks. Duralin picks allow an artist to highlight the bright clicking sound of the pick hitting the strings when playing acoustic, rhythm guitar, and fast single note  passages.