Features SELF-CENTERING: Dial Bore Gauge Made of aluminum alloy material, durable and long lasting. The easily adjustable bore gauge is self-centering for quick, accurate measurements SET INCLUDES: Drilling jig with insulated handle, self-centering measuring head, extension holder, spacers and matching case SUPER PRECISION DEPTH MEASURING BORE GAUGE: The measuring range is 50-160 mm. Two-point contact is used to detect geometric diameter measurement problems such as ovality and taper USE AFTER ZEROING: Before measuring, make sure the dial indicator pointer is set to the “0” setting and select the appropriate size measuring head for measurement EXTENDED RANGE: This drilling gauge with two-point contact system is used to measure hole diameters and also detect geometry anomalies such as ovality and taper Specification: Item Type: Inner Diameter Gauge Measuring range: 50-160mm Accuracy: 0.01mm Material: aluminum alloy Size: 50-160mm Measuring range: 50-160mm Package list: 1 x Inner Diameter Gauge with Handle, 1 x Protective Bridge (55mm), 12 x Side Head (#12: 105mm), (#11: 100mm), (#10: 95mm), (#9 : 90mm), (No.8 :85mm) (No.7 80mm) (No.6 :75mm) (No.5:70mm) (No.4:65mm) (No.3:60mm) (No.2 :55mm) (No.1:50mm )4 x replaceable side head (3 2 1 0.5) 1 pack of accessories for installing the inner diameter gauge 1 x plastic box (the color of the box is random and contains black and blue). Note: Please note that the new and old type of this product will be shipped randomly. Before ordering, make sure you don't mind. Package List 1 X Internal Diameter Gauge with Handle 1 X Guard Bridge (55mm) 12 X Side Head (No.12:105mm) (No.11.:100mm) (No.10:95mm) (No.9:90mm) (No.8:85mm) (No.7 80mm) (No.6 :75mm) (No.5:70mm) (No.4:65mm) (No.3:60mm) (No.2:55mm) (No.1:50mm) 4 X Interchangeable Side Head (3 2 1 0.5) 1 Pack Installation Internal Diameter Gauge Accessories 1 X Plastic Box (the color of box is random which has black and blue)