Features: Suitable for traditional milling machine and comprehensive processing machine Use with 400-600rpm rotating speed. The mechanical rotary measurement has no clamping error, and the repeated measurement accuracy can reach within 0.005mm. Specially designed 4mm probe for measuring small aperture and narrow groove. Anti-magnetic design is adopted for the rotary part of the lower end. Specification: Name: mechanical edge finder Material: carbon steel Size Large end: 20mm / 0.8in Small end:10mm / 0.4in Total length: 90mm / 3.5in Package list: 1 x Mechanical Edge Finder 1 x box 1Suitable for traditional milling machine and comprehensive processing machine 2Use with 400-600rpm rotating speed. 3The mechanical rotary measurement has no clamping error, and the repeated measurement accuracy can reach within 0.005mm. 4Specially designed 4mm probe for measuring small aperture and narrow groove. 5Anti-magnetic design is adopted for the rotary part of the lower end.