Indwangu yodonga elenga intuthu ngokuvamile yenziwa ngendwangu ye-silicone engashi.Yindawo engaguquki noma esebenzayo yokuvimbela intuthu engancishi ku-500 mm ukusuka ophahleni.Isetshenziswa kakhulu ezindaweni zokuthenga eziphakeme kakhulu noma eziphakeme kakhulu, izakhiwo zamahhovisi, izimboni, izindawo zokugcina izimpahla kanye nezinye izikhathi.Lapho isikhungo sokulawula umlilo sithumela isignali ye-alamu yomlilo noma isignali yokuzwa intuthu, udonga olulengayo lwentuthu oluguquguqukayo olubekwe ngaphezu kosilingi luzokwehla ngokushesha lufinyelele phezulu, kwakheka ukuhlukaniswa kwentuthu, okungavimbela ngempumelelo intuthu ukuthi ingagelezi iqonde ngaphansi kwesakhiwo. usilingi, bese kuthi isikhutha esikhipha intuthu sikhiphele ngaphandle intuthu yezinga lokushisa eliphezulu, okungathuthukisa umphumela wokukhipha intuthu endaweni yokulawula intuthu.