DescriptionSelf-Sealing Plugs will allow you to take pressure and temperature readings quickly and eliminate the need for leaving costly gauges or temperature indicators on the line. The plug is permanently installed in the line at recommended test points. The cap protects the valve and provides an additional positive seal. After the cap has been removed, either a test thermometer or a gauge adaptor with the proper pressure gauge attached can be inserted through the two self-closing valves in the plug. Readings are taken, adjustments or tests can be made, and when the probes are withdrawn, the two valves close. The protective cap is then reinstalled.