The Groz Combination Edge and Center Finder is the perfect tool for anyone looking for an accurate work location. The simple and convenient design makes it easy to get the job done right, every time. Manufactured from precision ground tool steel, these are case-hardened 45-48HRC. A very useful tool it is ideal to locate edges on any surface including flats, straight edges, shoulders and grooves as well as round work such as dowels or center points of circles. It is also useful to scribe lines on studs or wallboards.