Vet recommended: Feliway Classic is the #1 Vet recommended solution to help cats adjust to challenging situations and curb stress related unwanted behaviors | Reduces scratching and urine spraying: Clinically proven to reduce scratching and urine spraying in 9/10 cats. Results may be seen as early as 7 days | Drug free solution: Our diffuser mimics a mother's natural nursing pheromones, which helps to put cats at ease, and reduce conflict among cats | Covers up to 700 square feet: For best results, the Feliway Classic Diffuser should be plugged in continuously in the room where the cat spends the most time, and you should avoid plugging in the diffuser under shelves and behind doors, curtains and furniture | Refill Lasts up to 4 weeks: This product is the refill only - you need to purchase a diffuser separately. To maximize effectiveness, replace the vial every 4 weeks, and the diffuser every 6 months