This is 2 bottom trays and a sifter tray.  The sifter tray sits in the middle of the 2 trays until you need it.  You lift out the top tray (with litter) and dump it in the sifter tray (that is sitting on the 3rd tray)  You sift out the clumps and dispose of and then restack the trays.  It's really simple to use and pretty effective.