mˌʌltɪpəl tˈuːb sˈɛkʃənz ɪn wˈʌn ˈɑːnvəlˌoʊp mˈɪnɪmˌaɪzd ðə nˈʌmbɚɹ ʌv tˈuːbz ɹᵻkwˈaɪɚd ɪn ɐ ɹˈeɪdɪˌoʊ ɔːɹ ˈʌðɚɹ ˌæpɚɹˈæɾəs.
Multiple tube sections in one envelope minimized the number of tubes required in a radio or other apparatus.