Remote Field Testing (RFT): This is a fast reliable screening tool for the condition assessment of ferrous tubing (carbon steel, ferritic stainless steel and Duplex). Works typically at very low frequencies (100 Hz to 1 kHz) and very high signal gains (> 80 dB) can inspect up to 12 mm (1/2 in.) of carbon steel pipe. 

Typically two channels are used for examination, Absolute for wall thinning and Differential for localized defects RFT is very good at wall thinning measurement but less performing to pitting (as compared to ECT). To improve inspection results it is always advised to perform cleaning of the internal bore of tubes with some form of water jet lancing tool.