Igama elithi "3/4 inch tube" ngokuvamile libhekisela kububanzi obungaphandle (OD) beshubhu.Ukuze unqume ubukhulu bangaphakathi (ID), udinga ulwazi olwengeziwe njengokuqina kodonga.I-diameter yangaphakathi ingabalwa ngokukhipha kabili ubukhulu bodonga ukusuka kububanzi obungaphandle.Akunakwenzeka ukunquma ubukhulu bangaphakathi obuqondile beshubhu engu-3/4 intshi ngaphandle kokwazi ubukhulu bodonga.