Bests & Worsts Reviews from Amazon

This plastic tray replaces the disposable cardboard trays that are used in the ScopFree self-cleaning litter boxes. It seems a little expensive for simply being a plastic tray with a magnetic shield. Still, it seems like an improvement over the wasteful disposable cardboard trays that were originally designed for the self-cleaning litter boxes. The magnetic shield attaches to the waste storage cover, and does a pretty good job of sealing in odors from the waste storage. In the end, you will break even, compared to using cardboard trays, after 6-7 fills. After that, you will save about half the cost of the cardboard trays (the crystal litter costs about half as much as a tray filled with that litter). Update: The shield that attaches to the waste storage cover falls off at least once each week and then interferes with the moving rake. It would appear that the magnets in the waste storage cover are not quite strong enough to grip the metal tabs on the shield. I attached the shield permanently to the waste storage cover by removing the metal tabs on the shield and drilling a hole in the shield where the magnets attach. I then unscrewed the magnets and used a longer screw to attach the shield where the magnets used to screw in.