The crack depth determination by means of the potential probe method is based on the measurement of electrical resistance between two points on the surface of a metallic workpiece.

The Crack Depth Meter RMG 4015 measures crack depths on workpieces made of steel, iron and austenite and can also be used for cracks on copper, brass and aluminium and on most non-ferrous metals. Special probes are available for the measurement of inclined cracks. The RMG 4015 is an ideal supplement to PT or MT testing.