If you can't open the app, look on the original packaging or box the Zip came in.
The serial number is typically printed in very small text on the rear of the device. Fitbit Zip Serial Number
If the physical number is worn off or unreachable, you can find it in the Fitbit app by going to Account > Your Device, or via your desktop dashboard settings. If you can't open the app, look on
By locating and storing your Fitbit Zip serial number, you can utilize it to verify ownership with Fitbit Support if your tracker is lost and subsequently found by another user. If you can't open the app
Finding the serial number (SN) on a Fitbit Zip is crucial for support, as it is often worn off or tiny on the back of the device.