Pettex Fullers Earth Clumping Cat Litter is made from very absorbent clay mineral called Bentonite which helps to bind the strong odours found in cat urine. The benefit of Fullers Earth clay is that it clumps together when it is moist, allowing only the soiled litter to be removed and replaced. The reason that most people prefer clumping litter is due to the fact that traditional absorbent litter must be replaced frequently, while scoopable cat litter allows the solids and clumps of urine to be scooped out and discarded and a small amount of new litter to be added each time. A cat litter tray using clumping litter will last longer without the litter being completely replaced. Today, approximately 69% of the cat litter market is clumping cat litters.