[fwdude]

These never work right.

[ImJustAnotherOkie]

You just need a few dogs. They tend to keep the litter box empty.

[Lx]

I concur. They work but I never trusted it and it relies on the pipe you put the output into to never get clogged. I had it in the utility room but never left it on for more than an overnight trip.

I think the ones that rotate are probably better and the cat will get a fun ride.