The design closely resembles that of cockpits, but the real special feature of the new watch signed Hamilton, a preview of the models to be presented at the forthcoming Basel Show, concerns the Mach function, i.e. the measurement of an aircraft's speed in relation to the speed of sound. Pilots need only turn the watch's right crown to set the 'Pressure Altitude' (PA, the altitude indicated by an altimeter set to an agreed reference pressure value) and the 'Calibrated Air Speed' (CAS, the measurement of the speed at which an aircraft moves through the air), measured by on-board instrumentation, and on the bezel will appear the Mach number under ISA conditions (International Standard Atmosphere, the atmospheric model indicating the change in pressure, temperature, density and viscosity of the Earth's atmosphere over a wide range of altitudes). The chronograph case, 44 millimetres in diameter, houses a self-winding ETA-Valjoux 7750 calibre mechanical movement and is water-resistant to 10 atmospheres. For information: The Swatch Group Italy, tel. 02/575971.
