AJAX DoubleButton User Manual page 12

When cleaning the device body, use products suitable for technical
maintenance. Do not use substances containing alcohol, acetone, gasoline, or
other active solvents to clean DoubleButton.
The pre-installed battery provides up to 5 years of operation, considering one
pressing per day. More frequent use may decrease battery life. You can check
the battery status at any time in the Ajax app.
Keep new and used batteries away from children. Do not ingest battery, Chemical Burn
Hazard.
If DoubleButton cools down up to -10°C and below, the battery charge indicator