These probes are designed to save time and increase productivity by making some of the more difficult testing connections easier. These can be used to back probe weather pack style connectors found on many automotive sensors. Other applications include piercing and tapping readings on smaller gauge wires - using the included probe adapters. The probes work with most Test Lead Kits in the field - with a standard 4mm banana plug test lead connection. Set includes four probes - red, black, green, yellow. Test probes are 21 mm in length. Applications include automotive, industrial, HVAC, electrical, marine and more.