Rotate the red or black jack to move the piercing needle forward into the insulation. Rotating jack will not twist test lead while the needle is being screwed into wire. * Can handle wires from 0.030" diameter through 0.180" diameter insulation.* Overall length = 4-inches* High visibility bright yellow body.* Spring loaded slider holds wire centered for piercing needle.* Mates with any banana plug test leads including the AES ST3 Test Leads.* Mates with pin tip probe test leads. (see images below)* Materials consist of a Nylon body, hardened steel needle, brass socket.* Operating Voltage: 30VAC or 60V DC Max.* Current: 1 Ampere Max.Set includes two probes: one red, one black.These Probes will connect to test leads that terminate to Shrouded, Standard and Retractable banana plugs. Go to timestamp 10:00 see the Pomna probe in action in this video.