The tooth surface sensor of Mitech portable surface roughness tester MR200, with totally length of 78mm, main body length of 44mm, guide-head bearer length of 22mm, main body diameter of Φ10mm, core-insert sleeve diameter of Φ7mm, guide-head height of 1.5mm, It is the optional configuration of the surface roughness tester, mainly used for measuring the surface roughness for cylindrical gear with digital-analogy larger than 2mm. It needs with height gauge pillar to finish the measurement.