1.Accurately Measurement: The dial bore gauge accurately measures diameters ranging from 50MM (1.97') to 160MM (6.23') with a remarkable accuracy of 0.01MM (0.0003'). 2.Versatile Application: Ideal for measuring deep cylinders, pipes, and holes, detecting geometric abnormalities such as ovality and taper, suitable for use in automotive, manufacturing, and various industries. 3.Advanced Design: Features a twopoint system for precise hole diameter measurement and detection of geometry irregularities. The selfcentering and easily adjustable aperture gauge ensures fast and accurate results. 4.Kit Contents: This set features a hole gauge with an insulating grip, two selfcentering measuring heads, an extension bracket, gasket, and preinstalled housing to meet all your measurement requirements. The measuring heads are designed with a movable probe at one end and a replaceable probe at the other end, tailored to different aperture sizes.