To comply with Quality Assurance requirements, hot metal billets needed to be stamped with a batch number. The existing method was to use a hammer and handheld number stamp. This exposed the operator to high temperature and the difficulty of holding the stamp and hammer while wearing gloves.
The model PKL is a single impact model in which the piston is enclosed in the cylinder. This was modified so that the piston extended from the cylinder and could carry a stamp holder. The PKL provided consistent force so that the stamping was always even and legible, and the operator was situated away from the heat.