The Extech CG204 is a portable meter that can measure coating thickness non-invasively and recognize ferrous and non-ferrous substrates automatically. The tester use dual technologies to detect ferrous (magnetic induction measurement) and nonferrous (eddy current measurement) surfaces. It includes single and continuous measurement modes, direct and group working modes, 400-reading memory storage, and user-programmable high/low alarms. The CG204 includes two AAA batteries, a USB cable, software, calibration iron, calibration aluminum, accuracy standards, a pouch case, and a user handbook.