Canneed Magnetic Bottle Thickness Gauge (Magnetic Bottle Thickness Gauge) is a refined portable thickness gauge. It is used to measure the thickness of nonmagnetic material, such as plastic, glass, synthetics, aluminum and titanium, etc. The measurement accuracy is undistorted by the samples shapes. BTT is based on the theory of Hall Effect. For test, place the steel ball on one side of the sample and the probe on the other side. The Hall Effect sensor on the probe measures the distance from the probe tip to the steel ball. The calculator will display the real thickness readings