Jack txiv ntseej yog ib qho tseem ceeb hauv ntau qhov kev lag luam, suav nrog tsheb, kev tsim kho, thiab kev tsim khoom. Lawv yog siv los ruaj ntseg cov khoom nyob rau hauv qhov chaw thiab muab ib tug txhim khu kev qha fastening tov. Nyob rau hauv no blog, peb yuav delve rau hauv lub functionality ntawm jack txiv ntseej, hais txog cov lus nug ntawm seb lawv puas tshem tau thiab yuav ua li cas kom nruj lawv.