Izinkokhelo, iqhaza elikhulu lebhulonzi lebhulonzi, zingamaqembu amaningi futhi zingamaqembu amaningi ukuze zikhombise ibhulonzi lebhulonzi kanye nezinsiza zomthwalo. Iyinhloko yezimali yezinhlobo zonke zebhulonzi lebhulonzi futhi iyenza ngaphezu kwe-70% yezinqumo, ngakho-ke ubuciko bezinkokhelo kuyinhloko enhle kakhulu. Iyinhloko yezimbumba ezimbili, yezimbumba neplastiki.