Purina Tidy Cats Tidy Care Alert Health Monitoring Cat Litter (8 lb) – An innovative non-clumping crystal litter that changes color to help you monitor your cat’s health. Using pH-detecting technology, the silica crystals start off a neutral color and will turn blue, green, or yellow after your cat urinates to indicate potential issues (like urinary tract imbalance) once a baseline is established. This unscented, low-dust litter locks away moisture and odor effectively while providing a simple visual alert system – an easy way to catch early signs of UTIs or other urinary problems, so you can seek veterinary care promptly.