... : 10 PCS 2 Parameters Surface Roughness Tester (Ra, Rz)Specifications:Parameters: Ra, Rz Measuring Range:**** Ra: 0.05-10.00um/1.000 ... -400.0uinch**** Rz: 0.020-100.0um/0.780-4000uinchAccuracy: Not more than ... **** Humidity <80% SRT-6200 2 Parameters Surface Roughness Tester (Ra, Rz)