What he said, Casio, years ago. I wore it flying and mountain hiking
several times, too. It was reasonably accurate to about 10,000', then
it started running lower than either the aircraft altimeter or the trail
elevation signs said. Its barometric setting was by setting it to a
known altitude.

David

Peter Rathmann wrote:
On Mar 12, 2:00 pm, es330td wrote:
But pressure-based altimeter watches are commonly available. I used
to have a pretty cheap ($30) Casio with this function and I could
calibrate it either based on a currently known altitude or by setting
the sea-level pressure (i.e. the Kollsman window 29.92 setting when
appropriate). It updated the reading every 6 seconds and worked well
but I never used it for aviation other than for curiousity.