Accuracy 0.005MM;Quickly locate work edges;Probe Hardened \u0026 Precision Ground;Not necessary to rotate while measuring; LED lights instantly 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 away from ball seat; These excellent tools quickly locate work edges save time when finding positions on milling machines, jig borers etc etc; They employ a highly sensitive location sensor utilize a red pilot light which can be clearly seen an audible beeper The location of the end surface, outside \u0026 inside circle diameters can be detected; Shank Diameter: about 20mm Item length: about 160mm Ball Diameter: about 10mm Battery: 2 x LR1\/1.5V\/N Alkaline Battery (Size N\/LR1\/1.5v) (Not included) Color: silver Material: steel Package Included:1 Electronic edge finder with original box Only the above package content, other products are not included. Note: Light shooting 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.