vernier calipers, dial calipers, digital calipers, micrometers, dial indicators, test indicators, depth gauges, height gauges 538Features:Round mechanical body.Plastic dial adjustable ring.With adjustable tolerance markers.With dial locking screw.539Features:Round mechanical body.Plastic dial adjustable ring.With adjustable tolerance markers.Without dial locking screw.Measuring spindle sealed by means of rubber sleeve, thus preventing contamination by liquid and impurities.