General description Set of four HT Lead Testers allows for quick checks of ignition problems in-line to the spark plugs, which could result in misfires or non-running engines. These testers connect between the spark plug and HT lead, making it easy to identify issues with the output on HT leads and track ignition problems. Technical specifications Quantity: 4 x HT lead testers Compliance: CE, UKCA & RoHS compliant Usage Easy to use: install the testers between the spark plugs and HT leads, then run the engine. Other information Note: unsuitable for engines with deep recessed plugs and removable terminal nut.