Features CONVENIENT DESIGN - The ends of both contacts are made of steel treated at the head and precisely ground to a radius allowing proper clearance on the smallest hole the gauge will enter. Dual Action Handle - Dual action handles are rigidly attached to the contact pistons and automatically center. Durable to use: super quality, high rigidity, good wear resistance, durable use. QUICK HOLE CHECK - Helps to quickly check holes, slots and recesses up to 6 inches deep. Uniform contact pressure: The constant tension of the spring provides uniform contact pressure. Specification: Condition: New Material: tool steel Colour: as shown in the picture. Measuring range: 8-150mm Accuracy: 0.1 Quantity: 6pcs/set (ABCDEF) Scope of application: telescopic spring piston in the hole (or groove), can carry out the detection of inner diameter, used with micrometer or calliper, with knurled locking device. Features: The ends of both contacts are made of head treated steel and precisely ground to a radius allowing proper clearance on the smallest hole the gauge will enter. Constant spring tension provides uniform contact pressure. The dual action handles are rigidly attached to the contact pistons and automatically center. Helps to quickly check holes, slots and recesses up to 6 inches deep. Super quality, high rigidity, good wear resistance, durable use. Package list: 1 set of telescopic gauge (6 pieces) Package List