A shelf is very much like a slide-in tab that wraps all the way around the keyguard (or the keyguard frame):
 |
 |
| no mount | shelf |
There are two reasons why you might want to use a shelf to mount your keyguard if you’d like it be relatively difficult to remove the keyguard. You might also choose this message if you’re trying to replicate the screen protector that came with your case or make your own screen protector if your case didn’t come with one. You can find more about creating your own screen protector on the keyguard frame page.
After you select “Shelf” from the “mounting method” pull-down list, you can adjust the size of the shelf by changing the values in the “Shelf Info” section:
If you’re replicating the screen protector that came with your case, you can take these measurements directly from that screen protector. If not, you should experiment to ensure that the shelf isn’t so thick that it won’t fit between the tablet and the edge of the case opening. You should also ensure that the shelf isn’t so deep that it runs into parts of the case when inserted.