Toolmall Electronic Edge Finder 20mmX155mm， ±0.005MM
LED lights instantly and it beeps when probe touches conductive work pieceUse dry batteries to light the red lamp.Um5#, 1.5V x 2pcsThere is a safety spring puller which puts The ball precisely back to the position when ball breaks away from ball seatThese excellent tools quickly locate work edges and save time when finding positions on milling machines, jig borers etc etcThey employ a highly sensitive location sensor and utilize a red pilot light which can be clearly seen and an audible beeper The location of the end surface, outside & inside circle diameters can be detected..Specification:Shank Diameter: about 20mmShank length: about 160mmBall Diameter: about 10mmBattery: 2 x 1.5v  Alkaline batteries(not include)Package Included:1 x Electronic edge finder