Ooh okay you mean those shallower ones that're long, like you can slip under a bed, etc? I'm sorry there's so many styles and sizes - do you have a link or two, so I have an idea? Fena always "goes over" the side, for her accidents but Mao sprays litter like a madman so it's kinda hard for me to find litter boxes. Fena loves the biiiig shallow ones to stop the accidents (which is my problem at the moment to be honest) but Mao likes ones with deep sides (my lesser problem since it's so easy to just sweep it up and put it back).
I'd looked at tall sided boxes before but Fena hates them (too small for her highness) and some the front opening is too high and she doesn't always like to jump, though she can.
Just curious on my options with storage tubs/boxes - will scour Walmart.