These banana plug test leads are made of copper and a soft rubber for a nice flexible test lead. Every electronic techie should have these cables. Test leads kit comes with 10PCS of a tiny but powerful permanent magnet connectors, so quick and strong connections can be made. The end 4mm can be connected to a banana plug. Troubleshooting is now a breeze, no more alligator clips constantly popping out of terminals or shorting meters by hand. Specifically designed for embedded terminals in thermostats, control panels, sensors, switches, and alarm boards. Package include: 5 x banana to banana plug test leads, 10 x magnetic connectors. Not for use on live circuits.