This super value set of 6 bore gauges covers the range between 8 – 150 mm. For measuring the true sizes of holes,slots & recesses. Contact plungers of the gauge automatically self centre at all times and in all positions. The ends of the contacts are radius ground and hardened to provide clearance for insertion into the smallest hole the gauge will enter. Plungers are locked at any desired setting by a turn of the knurled screw at the end of the handle. The hole size being gauged is obtained by measuring over the gauge contacts with a caliper or micrometer. Satin chrome finish c/w wallet.