The M203 Altimeter / Indicated Air Speed Tester accurately measures pressure from 0 – 900 mm Hg (17.40 PSI) relative to absolute zero. Selecting the “ALT / IAS” unit from Program Mode converts the M203 to Altitude Mode for use in checking altimeter instrumentation. Pressing the ALT / IAS button toggles the M203 to Indicated Air Speed Mode for checking air speed instrumentation. Pressing the ALT / IAS button again returns to the Altitude display. English or S.I. units for Altitude and Indicated Air Speed are user selectable.

A timed leak test function is standard for Pressure, Altitude and Indicated Air Speed modes. The user sets the test period and starts the tests. The M203 displays Minimum, Maximum and instant values during the test period and then the leak rate per minute upon completion. Other features include Minimum / Maximum value capture, selectable damp rate, back light, programmable auto-off timer and record function. Four “AA” alkaline batteries provide more than 100 hours of continuous use.