Some dust masks include improvements such as having two straps behind the head (one upper and one lower), having a strip of aluminum on the outside across the bridge of the nose that can be bent for a custom fit, and having a strip of foam rubber on the inside across the bridge of the nose to ensure a better seal even if the aluminum on the outside does not fit.
sˌʌm dˈʌst mˈæsks ɪŋklˈuːd ɪmpɹˈuːvmənts sˈʌtʃ ɐz hˌævɪŋ tˈuː stɹˈæps bᵻhˌaɪnd ðə hˈɛd wˈʌn ˌʌpɚ ænd wˈʌn lˈoʊɚ, hˌævɪŋ ɐ stɹˈɪp ʌv ɐlˈuːmɪnəm ɔnðɪ aʊtsˈaɪd əkɹˌɑːs ðə bɹˈɪdʒ ʌvðə nˈoʊz ðæt kæn biː bˈɛnt fɚɹə kˈʌstəm fˈɪt, ænd hˌævɪŋ ɐ stɹˈɪp ʌv fˈoʊm ɹˈʌbɚɹ ɔnðɪ ɪnsˈaɪd əkɹˌɑːs ðə bɹˈɪdʒ ʌvðə nˈoʊz tʊ ɛnʃˈʊɹ ɐ bˈɛɾɚ sˈiːl ˈiːvən ɪf ðɪ ɐlˈuːmɪnəm ɔnðɪ aʊtsˈaɪd dʌznˌɑːt fˈɪt.