These spring load pull pins allow you to quickly retract and engage the plunger for locating, fastening and quick change operations. The housing of the pin is designed to be welded into place for strength. Pulling on the handle retracts the plunger fully into the housing of the pin. Releasing the handle allows the plunger to fully extend into position. The plunger is made from 1038 steel providing a tensile strength of 90 to 95 KSI on all sizes except the 5/8 which is made from 12L15 steel. The housing is made from unplated 12L15 steel for welding to fixture. The handle is plastic. The plunger and hex are zinc plated. The pull up force is approximately 5 lbs.