FELIWAY® Classic is the original diffuser from FELIWAY®, the #1 vet recommended brand. Designed to reduce common signs of cat stress such as scratching, urine spraying, hiding and stress caused by home changes. Using pheromone science, it creates a calming environment by sending calming messages. When plugged into a diffuser (not included), the refill provides up to 4 weeks of continuous calming, covering spaces up to 700 square feet. Trusted by millions of cat families and backed by 25+ years of expertise, FELIWAY® Classic offers an easy, effective diffuser for feline well-being and happiness at home.