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 (0.030inch through 0.180inch diameter). Tiny hole left in insulation can easily be sealed. High visibility bright yellow body.Red or black color-coded cap for easy identification. Rotating banana not twist test lead 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 Grounding Due To Design. The Tp81 Connects To Banana Jack Leads. Banana Jack Accepts All And Banana Jack Leads. Non-Rotating Banana Jack Prevents Leads From Tangling, Allowing You To Tighten/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 The actual product may have slight color difference or difference, which will not affect the use Colour: Material:Plastic Size:4mm Package Contents: 2x banana plug test probe(Red/Black)