Non-destructive insulation piercing contact - Insulation piercing clips contact insulated wires without cutting or stripping, protecting the wire during testing. Wide wire compatibility - Suitable for wires from 14 AWG to 22 AWG with a diameter range of approximately .03 to 0.18 inch. Easy operation - To establish contact, twist the bottom and move the black spring terminal to pierce the insulation and make the connection. Reliable testing performance - Designed to enable convenient voltage measurement while keeping insulation intact and wires protected. Two standards to choose from - Available in two standards: 2 mm and 4 mm. Use scenarios - Automotive diagnostics: quickly test circuits in car wiring without removing insulation. - Device and equipment repair: verify power and signal lines in electronics without stripping wires. - Field service and troubleshooting: connect test equipment to insulated leads in tight or damaged environments without modifying wiring.