The Roughness Tester PCE-RT-11 is a portable measuring instrument for determination of surface roughness according to Ra, Rz, Rq and Rt in just one device. The small roughness tester is especially designed for fast measuring of roughness. The roughness is a term of surface physics that describes unevenness of surface height. The roughness tester works according to the same piezoelectric micro probe principle like the highly accurate laboratory measuring instruments. The easy handling of the roughness tester as well as the high repetitive accuracy characterizes this device. After touching the button the piezoelectric micro probe of the roughness tester scans the surface within seconds and shows digitally, according to the preselected cut-off length, either the value Ra, Rz, Rq or Rt.