Long-life and high-accuracy RTD probes, also known as PRT probes, use a metal sensing element to measure temperatures at a wide operating range. They provide long-term stability compared to other types of probes. They typically have a probe, wired or wireless connection, and handle. Direct-connect RTD probes are used where quick and easy installations and removal are required. They do not have a cord or cable for installation. Threaded RTD probes have thread-mounted sensors for fixed-position temperature measurement of closed vessels like tanks or pipes. Flex-wire RTD probes have an insulated cable with a beaded junction on the sensing end with the terminal end connected to a meter or receiver. They are typically immersed in liquids and gases to provide measurements. Food, dairy, and pharmaceutical RTD probes are certified for measuring temperatures in designated sanitary areas. Flange-mounted RTD probes are fixed to ducts to measure the temperature of air flow.