... life should be considered. Calibration Type Characteristics: TYPE J (IRON vs CONSTANTAN) is used in vacuum, oxidizing, inert or reducing atmospheres ... recommended for longer life at these temperatures. TYPE K (CHROMEL vs ALUMEL ) is used in oxidizing, inert or dry reducing ... . Reliable and accurate at high temperatures. TYPE T (COPPER vs CONSTANTAN) is used or service in oxidizing, inert or reducing ...