I was using the Purina Second Nature Doggie Litter Box with peepee pads instead of Litter... Tanks to Oscar's Mom, I bought the "Big Squirt', which has 9" sides!! I took the grate out of it and threw it away and use just peepee pads in it. It is FABOULOUS!!!! I have to keep some pads underneath of it hanging out a little at the opening, because Riley has a tendancy to occassionally have one leg outside of it and one leg inside of it....
but other than that he uses it 100%
The Rascal Dog Litter Box Company offers two litter box sizes.