The Crystal litter trays make changing the litter so much easier.  They are disposable and last up to 30 days.  They absorb well and have very little dust. There is also less tracking, so I don't have to clean up as much.  They control odor well and keep smells at a minimum.   My cat does not have any problems using them.  They are compatible with my Scoop Free box.  These are a great option for anyone looking for a way to control odor, dust, and tracking from the litter box.