They are the old-fashioned type of wooden block, which is held in position by a strop passed round its shell and seized into a thimble-eye at the crown; the strop thus strengthens the shell and the block.
Yifashoni endala yebloko yokhuni, ebanjwe endaweni ngethwathwa edlula ngokurhangqela ikhoba yayo imeta kumakhamandela entunja kwisitshaba, ithwathwa libamba amandla kwikhoba nebloko.