@_brownie0_ With 1 hand since Middle School. In 1 second. I was horrible in High school I would walk down the halls to my next class and BIP.. and WOW the surprise.
@oelma__ Plumbob ! You use it like a level. It will always hang Plumb. You measure off the tip or lower on the string. Say you want to know if a 20ft.tall wall is plumb you drop it from the top and hold the string and see if the wall is level/plumb compared to the string.