Techno Line WT268 Instruction Manual page 39

Avoid contact with any corrosive materials.
Do not dispose this unit in a fire as it may explode.
Do not open the inner back case or tamper with any components
of this unit.
Batteries safety warnings
Use only alkaline batteries, not rechargeable batteries.
Install batteries correctly by matching the polarities (+/-).
Always replace a complete set of batteries.
Never mix used and new batteries.
Remove exhausted batteries immediately.
Remove batteries when not in use.
Do not recharge and do not dispose of batteries in fire as the
batteries may explode.
Ensure batteries are stored away from metal objects as contact
may cause a short circuit.