Is your cat peeing outside the litter box, scratching or hiding? These behaviors are likely caused by fear and anxiety. FELIWAY CLASSIC products are a clinically proven, drug-free solution to help alleviate many of the unwanted behaviors cat owners deal with. FELIWAY CLASSIC refills provide ?happy messages? to cats to make them feel calm and comfortable at home. By mimicking the natural feline reassuring messages (pheromones), FELIWAY CLASSIC helps cats happily adjust to pace of modern life. Use FELIWAY CLASSIC refill vials along with the FELIWAY CLASSIC diffusers (sold seperately) if your cat shows signs of discomfort like peeing outside the litter box, hiding, or destructive scratching. Reduces urine spraying in 9/10 cats. Can see results within 7 days. You may also consider if you anticipate changes in your home (moving, renovation, redecorating, arrival of a new pet, arrival of a new family member). Use the diffuser in the room where your cat spends the most time. FELIWAY CLASSIC Refill vials include one refill vial (diffuser head sold seperately). It is recommended to replace the refill every 4 weeks, even if a small amount of liquid remains in the vial (the vial will never be completely empty). #1 brand used and recommended by veterinarians. Clinically proven to work. Reduces urine spraying in 9/10 cats. Can see results within 7 days. Drug-free solution that helps reduce signs of stress such as peeing outside the litter box, scratching and hiding. CLASSIC Refill includes one vial per package that lasts up to 30 days (diffuser head sold seperately). 100% satisfaction guarantee.