This finder must first be calibrated over an empty section of the wall, and then it can be moved along the wall until it senses a change in density - such as the edge of a stud.
ðɪs fˈaɪndɚ mˈʌst fˈɜːst biː kˈælɪbɹˌeɪɾᵻd ˌoʊvɚɹ ɐn ˈɛmpti sˈɛkʃən ʌvðə wˈɔːl, ænd ðˈɛn ɪt kæn biː mˈuːvd ɐlˈɔŋ ðə wˈɔːl ʌntˈɪl ɪt sˈɛnsᵻz ɐ tʃˈeɪndʒ ɪn dˈɛnsᵻɾi sˈʌtʃ ɐz ðɪ ˈɛdʒ əvə stˈʌd.