Where is the serial number on a Electrolux microwave?

The data plate is on the rear of the microwave. For built-in models it may need to be slid out to read it.

Where the rating plate is1
  1. On the back panel

Source: Electrolux UK – Where can I find appliance's PNC number?

How old is my Electrolux microwave?

Copy the serial number from the plate, or paste everything on it.

Electrolux

All Electrolux appliances