Features 【Steel Material】Contact points are hardened tool steel with heat treatment and chrome plating on the surface.Super quality, high rigidness, good wear resistance, these telescopic inner diameter gauges are durable in use. 【Function】6pcs/set telescopic gauge can assist in quick checking of holes, slots and recess up to 6 inch deep. Easy to adjust for accurate measurement. Accuracy: 0.1. Double action handles are rigidly attached to the contact plungers and are automatically self-centering. 【Easy to use】Use the telescopic gauge to expand in the hole to be measured, lock it in place, and then take it down, and measure with micrometer to determine the final hole size. 【Precision Ground】The ends of both contact are head treated steel and precision ground to a radius allowing proper clearance on the smallest hole the gauge will enter,used to obtain the exact size of holes and slots, which is suitable for factories, schools, offices and other places. 【Wide Application】Constant spring tension delivers uniform contact pressure.Used for measuring holes, slots, grooves, and recesses in woodworking, metalworking, machining,and pattern-making applications. Specification: Condition: Brand new Material: Tool steel Color: Shown as picture Measuring Range: 8-150mm Accuracy: 0.1 Quantity: 6Pcs/Set (ABCDEF) Scope of Application: Telescopic spring piston in the hole (or groove), can conduct inner diameter detection, used with micrometer or caliper, with knurled locking device. Package List: 1 Set Telescopic Gauge (6pcs) Package List