CareFusion MicroCO Operating Manual page 27

Do not open the battery cover when the device is turned
on.
The operator should not touch the contacts of the battery
and the patient at the same time.
Waste Battery Regulations.
The MicroCO meter has an internal battery with a life of approximately
10 years. This battery supplies the sensor signal conditioning circuit
continuously to ensure instant start up.
When the battery has expired, the following warning message will be
displayed:
and the alarm will sound when the unit is first turned on.
When this occurs, the CO meter must be returned to CareFusion, or an
authorised agent, for battery replacement.
Sensor life is greater than 2 years. The sensor life depends upon both
the amount of exposure to CO and other gases and solvents such as
alcohol and cleaning fluids.
Dispose of the waste battery in accordance with EU
25