* Be compatible with the principles of ASTM D 4417-B,IMO MSC.215(82), SANS 5772, US Navy NSI 009-32, US Navy PPI 63101-000. When measuring the roughness of a surface, the sensor is placed on the surface and then uniformly slides along the surface by driving the mechanism inside the tester. The sensor gets the surface roughness by the sharp built-in probe. This roughness causes displacement of the probe which results in change of inductive amount of induction coils so as to generate analogue signal, which is in proportion to the surface roughness at output end of phase-sensitive rectifier. The exclusive DSP processes and calculates and then outputs the measurement results on LCD. * Highly sophisticated inductance sensor. * Small in size, light in weight and easy to use. * Manual or automatic shut down. * Metric /Imperial Conversion. * With average calculation function. * Use “USB data output” and “RS-232 data output” to connect with PC. * Provide “Bluetooth ™ data output” choice.