Well Marco - you have left out some vital information...
The type of device and its make and model - always useful to know...
If it operates from plug in the wall mains-electricity then the input voltage for your "model" will be the same as the other appliances in your house - USA=110V and other places generally 230V...
If it's battery operated then look into the battery compartment - you can usually get a clue in there...
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