Optical and acoustic For the exact determination of work piece zero points and drilling points on milling machines, drills, processing centres, etc.. On contact, the spring-loaded probe ball in the axes X and Y with the work piece, the circuit closes, and the omnidirectional display lights up. The 3D type also has a safety spring path of 2 mm in the Z axis. The reference length must first be measured in a presetting device and taken into account. ± 0.01 mm. Ball probe Ø 10 mm