Where is the serial number of my Philips hand blender? If you want to register your hand blender or contact us with a question about it, you will need your serial number. Where to find your serial number: Press the release button on the motor unit to remove the blender bar or chopper coupling unit. Check at the bottom of the motor unit, near the release button. Where to find the model number The model number is located at the same place as the serial number. The format is: HRXXXX (HR followed by 4 digits).