Magnetic couplings allow a physical separation between input and output shafts, precluding the use of shaft seals, which eventually wear out and fail from the sliding of two surfaces against each another.
mæɡnˈɛɾɪk kˈʌplɪŋz ɐlˈaʊ ɐ fˈɪzɪkəl sˌɛpɚɹˈeɪʃən bᵻtwˌiːn ˈɪnpʊt ænd ˈaʊtpʊt ʃˈæfts, pɹɪklˈuːdɪŋ ðə jˈuːs ʌv ʃˈæft sˈiːlz, wˌɪtʃ ᵻvˈɛntʃuːəli wˈɛɹ ˈaʊt ænd fˈeɪl fɹʌmðə slˈaɪdɪŋ ʌv tˈuː sˈɜːfɪsᵻz ɐɡˈɛnst ˈiːtʃ ɐnˈʌðɚ.