... measures the thickness of the poured concrete slab of non-metal like structure,concrete,wall,girder,bar,pole,wood and ... ×80mmExtension Bar:φ25×600(mm)(3 piece)Work PrincipleDJLC-A concrete thickness gauge is composed of signal transmit, connector, signal ... read and auto lockup,real-time thickness display then reduced man-made error andIntensity of labourTransimit electrode and receive electrode ...