Kullin kwano nau'in kulli ne wanda ke haifar da tsayayyen madauki a ƙarshen igiya ko layi. Ana yawan amfani da shi wajen tuƙi, hawa, da sauran ayyuka inda ake buƙatar amintaccen madauki. An kafa kullin ta hanyar yin ƙaramin madauki a cikin sashin tsaye na igiya, sa'an nan kuma ya wuce ƙarshen aiki ta hanyar madauki, a bayan sashin tsaye, da kuma komawa ta hanyar madauki. Lokacin da aka ɗaure shi, kullin yana samar da amintaccen madauki wanda ba zai zame ko ya koma baya ba a ƙarƙashin tashin hankali.