This Type J thermocouple is designed for use with our Westberg Cylinder Head Temperature Gauge, Part No. WBT-2C1 (sold separately). Self-powered thermocouples generate a small amount of voltage based on the difference in temperature from the hot (probe) end and the cold (cable) end. Sold individually.
This ring size fits spark plugs with 12mm threads such as Champion A-Series Spark Plugs. The 4-foot lead can be extended by adding a Thermocouple Extension Cable (Part No. 1086, sold separately).