This is a plumb bob that won't drive you mad. All the annoying aspects of traditional plumb bobs have been designed out. The flat sides prevent rolling and allow the bob to 'settle' very quickly. The 8' of nylon cord is held on a windlass which clips neatly into the pencil slot when not in use. A protective cap prevents the point from damage when not in use. It's a 'just gotta have' type of tool as well as being extremely useful. Length 90mm. See Marking Pencils section for pencils to go with your plumb bob.