This is just an excellent tray-house with a grid.
We have 2 cats. One kitten has a medium length coat, the second kitten, apparently, will be long and fluffy. We used wood filler almost all the time, since most of the clay ones were dusty, and the clumping ones stuck to the paws.
Used in a tray-house, in which there was no grid. Because of this, upon contact of sawdust with moisture and cats with filler, the fine dust, into which it all turned, on the second day of changing the filler to clean, See full review