Brass Baffles with Quick Connect or 1/8 inch NPT threads. 1/8″ male NPT system connection and 1/8 inch female NPT on the gauge tube connection. This baffle will extend the life of your gauge tubes by keeping dust and oil vapors from condensing in the tube. It provides a labyrinth with eight 90 deg. turns between the vacuum system and the tube. The large internal diameters provide fast response and are easy to clean. Note that standard 1/8 inch NPT thermocouple and Pirani tubes are .403 inch outside diameter. O-ring in quick connect is Buna-N.