The NEW Mahr Pocket Surf IV EGH-1026 Portable Surface Roughness 5µm. Surface parameters include Ra, Ry, Rmax, Rz. While the new Pocket Surf® IV looks virtually the same as when it was introduced over 30 years ago, it contains updated electronics and employs significant product use improvements. The Pocket Surf® IV is compatible with all the probes and accessories that are currently available. Some of the improvements include: Ability to view the three parameter results with one measuring cycle; Digital calibration which eliminates the manual screwdriver and potentiometer calibration process; New output connector providing three cable formats and MarCom compatibility. The Pocket Surf® IV is still the easiest to use portable Surface gage available.