Standard taper inner joints or spherical ball joints at bottom of main tube and on the end of the 75-degree sidearm tube. Top of main tube has a threaded joint. Both joints are of the same size, unless otherwise requested. NOTE: Threaded joint makes o-ring seal when nylon bushing is screwed into adapter and accommodates up to 7 mm thermometers, gas inlet tubes, etc. Suitable for vacuum. Threaded joints are supplied complete with nylon bushing and o-ring.