Metal Protection Tubes may look like thermowells and sometimes even be called thermowells, but they are not thermowells. Metal protection tubes are outside the ASME 19.3TW Thermowell standard because they are constructed from pipe rather than bar stock. They are available in any pipe material construction and process connection. For a quick response to changes in temperature these can be ordered with “Fast Response Tips”, reducing the response time to a step change in temperature from minutes to seconds. These are an excellent solution to duct and other long immersion applications where bar stock construction is impractical.