A lever inspection gauge is a portable precision measuring tool that uses a lever mechanism to mechanically amplify small displacements of the measured size, and directly displays the deviation value through a pointer or reading window. Built in constant force spring ensures consistent force measurement in both forward and reverse directions, eliminating human error. Fully mechanical structure, maintenance free, suitable for explosion-proof or outdoor scenarios. Applied to batch testing of connecting rod aperture in automotive engines; Quick determination of groove width for precision stamping parts; Sampling inspection of root thickness of aerospace blades; Online monitoring of mold cavity wear.