excellent sand
I've tried several types and ended up coming back to this one. Even though it's not clumping, it absorbs urine well and we never notice any unpleasant smells. We only change it when we've already forgotten when we last put it in. It probably helps that our cat's litter box is made of stainless steel and our cat is a spayed female. It spreads around just like other types, maybe even less than some I've noticed all over the flat because the pellets were bigger. Here, most of it stays on the mat in front of the litter box, and we pick up the rest with a handheld vacuum when needed.