https://www.lanequalitys.com/products/sr220-surface-roughness-tester.html SR220 Surface Roughness tester has 20 roughenss parameters. Using DSP chip to control and data processing, high speed, low power consumption. Electromechanical integration design, small volume, light weight, easy to use. Multi-info Display: measurement information, menu prompt, fault and power switch information indicated. SR220 tests stable and accurate, and has gained users loving.All Rights Reserved