FELIWAY is the original feline pheromone brand, and inventor of the category, supported by 25+ years of feline stress expertise. FELIWAY Optimum is a patented pheromone discovery developed by the #1 vet recommended brand to help reduce common signs of stress in cats such as: scratching, urine spraying, conflicts between cats, and excessive hiding. It is drug-free and used by millions of cat families to help ease cat's stress related behaviors by sending them reassuring messages, similar to natural pheromones. Cat owners reported a 70%+ reduction in scratching, urine spraying, conflict, and hiding when using FELIWAY Optimum. The diffuser continuously releases calming pheromone analogs up to 30 days, to help comfort your pet. Simply plug into an open outlet with 4+ feet of space to diffuse, with vents pointed upright. Safe to use - while pheromone analogs may help your cat, they won't affect humans or other pets.