# Managing eInk Kindle serial numbers

If you have upgraded from an earlier version of the plugin, any existing eInk Kindle serial numbers will have been automatically imported, so you might not need to do any more configuration.

Please note that Kindle serial numbers are only valid keys for eInk Kindles like the Kindle Touch and PaperWhite. The Kindle Fire and Fire HD do not use their serial number for DRM and it is useless to enter those serial numbers.

### Creating New Kindle serial numbers:

On the right-hand side of the plugin’s customization dialog, you will see a button with an icon that looks like a green plus sign (+). Clicking this button will open a new dialog for entering a new Kindle serial number.

- Eink Kindle Serial Number: this is the unique serial number of your device. It usually starts with a ‘B’ or a ‘9’ and is sixteen characters long. For a reference of where to find serial numbers and their ranges, please refer to this mobileread wiki page.

Click the OK button to save the serial number. Or Cancel if you didn’t want to enter a serial number.

### Deleting Kindle serial numbers:

On the right-hand side of the plugin’s customization dialog, you will see a button with an icon that looks like a red "X". Clicking this button will delete the highlighted Kindle serial number from the list. You will be prompted once to be sure that’s what you truly mean to do. Once gone, it’s permanently gone.

Once done creating/deleting serial numbers, click Close to exit the customization dialogue. Your changes will only be saved permanently when you click OK in the main configuration dialog.