63811-1000 Plier Crimping Tool for Open Barrel Terminal. When a crimping tool is used on a terminal, two crimps take place at the same time. One is the electrical connection between conductor and terminal. The other is the insulation crimp which provides strain relief against vibration and tension. It is important that the electrical connection is gas tight without any voids between the wire strands and the terminal. If there any voids present, then corrosion can occur causing resistance and excessive heat which damages the electrical connection.