PN Ring/Locking Fork Terminals Panduit PN Ring/Locking Fork terminals are designed to assure secure connections in high vibration applications. These terminals are nylon insulated and the metal insulation grip sleeve holds to the wire as a protection to the crimp joint. The PN ring/locking fork terminals contain internal barrel serrations that guarantee good wire contact and high tensile strength. These terminals exhibit UL flammability UL 94V-2/HB and a maximum insulation temperature of 105°C. The PN ring/locking fork terminals are UL and CSA rated up to 600V per UL 486A/B.