We tried the environmentally-friendly NON-clumpable “World’s ‘Best’ Cat Litter” due to a full rebate. Even for free I only used it not to waste it. I think it was corn pellets, though it could have been wood pellets like the Feline Pine– I can’t recall any more, but both of these litters were awfully difficult to use. My fiance hated because it tracked hard pieces everywhere (he said besides being messy it damages the wood floor when stepped on), and the cats didn’t seem too thrilled with the texture. Since it wasn’t scoopable and disintegrated into basically sawdust when peed on, it was laborious to remove the wet crumbly piles, but if I didn’t, it smelled and cat would be stepping in it to use the box again.