Telescopic Gauge Set 6pce 8-150mm OverviewKnurled handles, locking nuts and automatically self-centering plungers with constant spring tension for uniform contact pressure. Quick inside measuring of cylinders. Indirect measurement by outside micrometer. Includes 8-12.7, 12.7-19, 19-32, 32-54, 54-90 and 90-150mm gauges.