70 out of 100 Good
The litter built for the machine, by the company that built the machine. Whisker, the American maker of the Litter Robot, formulates GreatLitter from sun dried Wyoming sodium bentonite specifically to cycle cleanly through its own boxes, and it arrives at No. 41 with seventy, a card with two strong fronts and a familiar conscience cost.
Clumping and odour each score four and a half, the qualities that matter most in an automatic tray. The clumps set large and hold together, surviving the rake and leaving the bed looking genuinely fresh after a cycle, and the odour control masks a used box well. Tracking is decent at three and a half, the grain mostly contained, while dust is the soft spot at three, a little more haze on the pour than the engineered leaders of the clay category.
Sustainability sits at two, the strip mined floor that every bentonite shares. It is the anchor that keeps an otherwise capable litter in the lower middle of the list.
It is, in effect, a companion product to an ecosystem rather than a shelf litter. For the owner of a Litter Robot who wants the litter engineered for it, it is a sensible and well matched choice, clumping hard and controlling odour where the machine needs it most. For everyone else, more available clays do the same work. A purpose built litter, best understood as part of the box it serves.