Air conditioner tubing is inspected inline after extrusion. An encircling coil tests for outer surface defects and checks that the walls of the interior chambers are intact. It is specially designed for this tube shape.The eddy current signals are transmitted to an eddy current inspection unit that analyzes the signals for defects. The unit also controls marking of the defects and sorting of the test piece. Test results can be printed out immediately or stored for future reference.