Operation Manual

5
There is a highly sensitive pressure sensor inside each Echo-a1 or
Echo-a2 cycle computer, and there is a hole at the bottom of each
main unit for measuring the pressure. You should always keep the
hole clean to avoid incorrect measurement and must not poke a
needle or any pointed article into it to avoid damage. The
atmospheric pressure measured by the sensor will be converted into
current altitude. After using your Echo-a1 or Echo-a2, you are sure
to get a lot of fun from riding with it.