4 stars because at least it was cheap. Under picture 5 on the application instructions you can see: "use the smoothe card provided to lightly..." There was no smooth card, whatever that is. I could not apply it without some small bubbles and this protective layer becomes all scratched up by the stylus very quickly. But this is not a problem as the small bubles and the scratches can only be seen when the DS is turned off, they are not visible when using the DS. I'll buy some more of this and replace it regularly, as I would rather have the kids apply scratches to this protective layer than the actual display.