ED400 Coating Thickness Gauge is the improved model of the ED300 Gauge. The performance is prominently improved. The gauge is used to measure the thickness of the insulating coating on nonmagnetic metals. It is mainly used to measure the anodic oxide coating on aluminum alloy profiles, aluminum composite panel, and other aluminum workpieces. It can be used to measure the thickness of the insulating coating thickness on other non-ferrous metals, also can be used on paper and plastic foil.