Type K thermocouples are the most common type of thermocouples used in electric kilns and with pyrometers. These thermocouples are purchased in bulk directly from the factory to save you money. The manufacturer is ISO/IEC 17025 certified. Total length is 12" and the diameter is .46" to fit in a .5" diameter hole. This thermocouple is interchangeable with Alpine thermocouples and works with the analog pyrometer we used to sell.