General Tools Brass Plumb Bobs General Tools professional quality Brass Plumb Bobs have been a staple of the masonry, carpentry and surveying industries for more than 50 years. This retractable plumb bob is also equipped with a hardened steel point that has standard 10 to 32 threads; The tool's hardened steel point is accurate to within 1/100 and is easily replaceable. . . Pack of 1 WARNING: This product can expose you to Lead, a chemical known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov - Lead