I have 2 that use the washable pp pads and 3 that will only go outside. So i have both i guess. The pp padder's will also go outside. I have a mess on my hands during bad weather as NONE of them will step outside if it is even damp. I end up taking them with an umbrella one at a time to the grass. I wish the 3 outsiders would use the pp pads but they won't.