Okay kiddo, so you know how sometimes when you're listening to the radio, you hear some stations really clearly, but others are fuzzy or don't come in at all? That's because different radio stations use different frequencies to send out their music and talk shows.
A multi-band device is like a special radio that can tune in to more than just one frequency range. Instead of only being able to listen to one type of station, a multi-band device can pick up signals from a bunch of different frequencies all at once.
It's kind of like having a bunch of different radios rolled into one, but instead of needing to switch between them, you can just use the multi-band device to scan all of the frequencies it's capable of receiving at once. So whether you want to listen to news, music, or sports, a multi-band device can help you find a station that's clear and easy to hear.