1. Dual action handles are firmly connected to the contact bump and center automatically. 2. Assists in quick inspection of holes, slots and cutouts up to a depth of 6 inches. 3. The ends of both contacts are made of head-treated steel and precision ground to a radius that gives a reasonable distance to the smallest hole where the measuring device penetrates. 4. Constant spring tension ensures even press pressure. 5. Super quality, high rigidity, good wear resistance, durable in use. Specification: Features: The articulated handles are firmly connected to the contact bump and center automatically. Useful for quick inspection of holes, slots and recesses up to a depth of 15.2 cm. The ends of both contacts are made from head-treated steel and precision ground to a radius that provides the correct clearance for the smallest hole that can hold the measuring device. Constant spring tension ensures even press pressure. Super quality, high stiffness, good wear resistance, durable in use. Specification: Condition: New Material: tool steel Color: as shown Measuring range: 8-150mm Accuracy: 0.1 Quantity: 6 pieces/set (ABCDEF) Application: Telescopic spring piston in the hole ( or in the groove), can determine the inside diameter, is used with a micrometer or caliper, with knurled locks. The package contains: 1 set of telescopic gauges (6 pieces)