MiniTest 70 The MiniTest 70 is a lightweight and handy coating thickness gauge (DFT gauge) in a pencil format with a built-in sensor. MiniTest 650 Rugged coating thickness gauge with fixed external probe for all non-magnetic coatings on steel and all insulating coatings on non-ferrous metals. MiniTest 700 Handy, accurate and versatile coating thickness gauge for use in laboratories, factories and on the go. MiniTest 7400 High-end coating thickness gauge with a wide selection of external, interchangeable sensors. MikroTest MikroTest is an extremely robust coating thickness gauge, which measures the thickness of non-magnetic coatings on steel substrates on the magnetic attraction principle.