Dura Lead replacement lead is designed exclusively for The STKR Mechanical Carpenter Pencil. This package includes 4 pieces of Dura Lead, packed in a durable storage tube. Dura Lead is 18% thicker than traditional carpenter pencil lead.  It is medium density and stands up to the rigors of construction. Dura Lead's patented grooves lock into place and never slip while being held by The STKR's rugged jaws. Quickly shape the lead for a razor sharp tip that is still durable. Get closer to a speed square than any other pencil. Never sharpen a carpenter pencil again...Get the lead out!