The Klein Tools 1659 Series PVC-Covered Chicago Grips have a specially machined serpentine jaw which allows an insulated conductor to be inserted through the jaws. This eliminates the need to strip insulation from the conductor first. All Klein grips are manufactured from custom drop-forged steel that is machined and heat treated for excellent durability. Each grip is individually hand inspected and actuated for proper function. Grips are also rigorously tested and pulled to rated load to ensure the highest quality and reliability.