The Big Foot Bolt Hole Marker, hand held, is one of the most important tools for saving time on the job. It can be used as a foundation bolt locator, HD bolt locator, ledger bolt locator, and plate bolt locator as well as for bolt hole marking. The Big Foot Bolt Hole Marker is so accurate you can drill holes 1/16" over size, leading to nicer fitting and cleaner jobs. Five different marks: 1/2", 5/8", 3/4", 1", and 1-1/4"Ball bearing lock keeps the indicator in placeMarks 2 x 4 or 2 x 6 plates