Like another reviewer, I was concerned with the impact of the permanent liners on the environment and decided to try the paper liners. While they don't last a full month, at least in our home (we have two cats), they do last up to 3 weeks with regular cleaning of the box. It's great that you get 6 liners in one purchase. I'll definitely continue using these and would highly recommend them.
Make your cat happy and buy these!
Flip Paperboard Liners - 6 Pack
I love these litter boxes and liners. I recommend them all the time to family and friends. I have five cats so believe me when I say I have tried numerous kinds of boxes. Nothing comes close when you pair these liners and a good clumping litter. No smell and no mess and with the solid construction of the box no leaks. My big orange tabby thinks there great too :-)
Such an easy way to keep the litter box tidy - love these!