Quickly locate work edges, Probe Hardened and Precision Ground Not necessary to rotate while measuring, LED lights instantly and it beeps when probe touches conductive work piece There is a safety spring puller which puts The ball precisely back to the position when ball breaks from ball seat These excellent tools quickly locate work edges and save time when finding positions on milling machines, jig borers etc etc They employ a highly sensitive location sensor and utilize a red pilot-light which can be clearly seen and an audible The location of surface, outside and inside circle diameters can be detected : Metalworking Model Number: Electronic edge finder Material: Main body stainless steel (The edge finder is mainly used to determine the X and Y zero point offset values of the origin of the workpiece coordinate system in the machine tool coordinate system, and can also measure the simple dimensions of some workpieces.) Commonly used in milling machines, end machines, and other mechanical equipment. Notes before buying: The appearance of different batches of products will be slightly different, and the appearance will not affect the use, subject to the actual product received! Color: Silver Material: Stainless steel Package Contents: 1 x Electronic Edge Finder Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.