- Push firmly to remove the measurement unit from the rubber housing (Fig.1)
- Ensure that there are no water droplets on the measurement unit, dry it with a paper towel
- Remove the 4 screws with a small screwdriver and remove the battery housing cover (Fig.2)
- Carefully remove the empty batteries and insert new batteries (two LR44 coin batteries).
- Screw the screws back in the battery housing to close it again.
- Push the measurement unit back into the rubber housing.
Note: only use the recommended batteries, and make sure you have properly assembled the device before use.