Take a close look at the retaining tabs in the case top half, at the lower right side, where it slides over the keyboard. I had to file it a little so it didn't scratch the lower case half of the N900. Also, the top case half on mine was loose and would pop out with moderate pressure, so I use two pieces of insulation tape on each side, in side the top part of the case. Nice 'n tight now. Of course, there are many different kinds sold on EBay, so yours might not have these issues.