In conjunction with REC, the DIS records two resistivity curves of different depths of investigation and a SP curve. Combined with MSFL log, three resistivity logs can be converted to the resistivity of flushed zone, the invasion diameter and the true resistivity (Rt). The tool is well used in wells drilled with medium and high resistivity drill fluid, for example, fresh water, air and oil-based mud. The tool is usually run simultaneously with other 530-series tools or sondes in conjunction with REC, NEC and TCT.