Puncture clips allow the user to provide the precise pressure required to puncture the insulation of various wire types and sizes. design is both cost-effective and convenient, it can bequickly removed to expose the puncture tip for any required sharpening, extending the life of the product and eliminating the need to completely replace the test clip as with other models on the market. The red and black color-coded barrels providequick circuit identification and the bright yellowbody is easy to locate in low light conditions. The test clip offers further convenience with its 'in-line retention'feature. Once the test clips are attached to the leads, the test leads can be removed from the clips for testing in another location. 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 needle pierces the insulation to make contact with the conductor.(Damage is fairly minimal) Colour:As Shown Material:plastic Size: 4mm Due to different batches, there may be differences in product appearance and printed text, which not affect use Package Contents: 2 x Insulation Wire Piercing Puncture Probe 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 a little different from the real thing. The measurement allowed error is 1-3cm.