Made of cast iron in Kyoto, Japan by KOD, these plumb bobs are carefully machined and balanced to the center line of the bob. Weighing in at almost 9 ounces, the weight of this plumb bob makes it a great choice for outdoor use, especially in windy conditions. A removable brass nut, threaded into the center of the bob, provides the point for the user to tie any string as a plumb line (string not included).