Puncture clips allow the user to provide The precise pressure requiredtopuncturethe insulationof various wire types and sizes. The unique design is bothcost-effective and convenient, it can bequickly removedto expose the puncture tip for any required sharpening,extending the lifeof the product and eliminating the need to completely replace the test clip as with other models on the market. Use:attach it to the banana plug and then the other end can be hooked onto the insulated wire, by turning the red or black end of the clip the sharp needle pierces the insulation to make contact with the conductor.(Damage is fairly minimal) Specifications Size: 96*19.3mm/4*1in Probe tip: 2mm /0.08in Colour: yellow/black/red Packaging: Pack of two