Umphakamo wofakelo lweebhokisi zesiphambuka ezinobungqina bokudubula ngokubanzi ibekwe e 130 ukuya 150 iisentimitha.
Ezi bhokisi zizixhobo ezikhethekileyo zokuhambisa umbane, eyenzelwe ngokukodwa ukusetyenziswa kwiindawo ezinomngcipheko ophezulu. Ngokungafaniyo neebhokisi ezidityanisiweyo zasekhaya eziqhelekileyo, Iibhokisi zesiphambuka ezinobungqina bokudubula ziye zalungiswa ngeendlela ezahlukeneyo ukuze zixhotyiswe ngesakhono sobungqina bokudubula.. Olu hlengahlengiso lubenza bafaneleke ngokukodwa kwindawo apho qhuma izinto zinokubakho, ukuqinisekisa ukuhanjiswa kwamandla okukhuselekileyo nokuthembekileyo kwezo ndawo zibalulekileyo.