Royal Canin Indoor Adult addresses these issues for indoor cats, 1 to 7 years of age. Indoor cats spend more time sleeping, eating and grooming rather than exercising which can result in slower digestion, soft, smelly stools and weight gain. Also, increased grooming can lead to more hairballs. This formula helps with strong stool odour caused by smelly hydrogen sulphide can be a problem when cats live exclusively indoors, plaque and tartar build-up and minimizing hairballs.