Make contact with insulated wires without cutting or stripping insulation. Spring loaded double "V" clamp holds wire centered for piercing needle. Pierces insulation on wires from 22 to 14 AWG (0.030 inch through 0.180 inch diameter). Tiny hole left in insulation can easily be sealed. High visibility bright yellow body. Rotating banana jack prevents test lead twist while the needle is screwed into wire. Probe pierces insulation on 14, 16, and 18 gauge wire. You control needle depth to minimize insulation damage. Essential for use under hood or under dash. Use it on fuel injectors or sensors while providing complete insulation to ground due to design. The TP81 connects to banana jack leads. Banana jack accepts all standard 4mm banana plugs. Non-rotating banana jack prevents leads from tangling, allowing you to tighten or loosen clamp while still connected to the test lead. For use with test leads with 4mm banana plugs. Tested to 70V DC. Car wire tester, voltage tester, wire clip voltage test tool. Color: Yellow Material: Plastic and metal Size: 2 mm Package Contents: 2 x Insulation piercing clip Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing. Measurement allowed error is +/- 1-3 cm.