Buoy-type pneumatic measuring instrument with mechanical gauges, meter compared with the following advantages: 1, the workpiece can be measured parameters of various lengths, shapes and position error, especially with mechanical gauges and measuring instruments for the measurement of certain difficult to solve, such as: measured hole diameter, the hole diameter, the narrow groove width, relatively easy to achieve with pneumatic measuring. 2 meter high magnification. Human error is small, does not affect the measurement accuracy; no mechanical friction at work, so there is no return errors. 3. The method of operation is simple, easy reading cellar, capable of continuous measurement, in the simultaneous measurement of multiple dimensions, can see at a glance whether the individual dimension grid station. 4, to achieve the measuring head and the surface is not in direct contact with the measured grant to reduce the impact on the measurement results of measuring force, to avoid scratching the surface under test, measurement of thin-walled parts and soft metal parts is particularly applicable. Due to non-contact measurement, the measuring head can reduce wear and extend life. 5, using a hose connection between the body and the measuring head pneumatic measuring instrument, can achieve long-distance measurement. 6, simple structure, reliable work. Adjustment, use and maintenance are very convenient. Purpose: coupled with a variety of manufactured probe measurements can be achieved as follows: diameter, diameter, width, two pitch, depth, thickness, roundness, taper, concentricity, straightness, flatness, parallelism vertical degrees, the air permeability and tightness. Requirements: Clean dry air source for 0.3-0.7MPa above, please use the metering site QGL-3-type air filter. Buoy can be more than one meter assembly, multi-parameter measurements.