Milemont Feliway Refills 48ml Vials, 12 Pack Comfort Zone with Feliway helps end urine marking and scratching; includes a 48ml refill bottle (1.62 oz) Mimics feline facial pheromone to reduce, or eliminate, stress-related behavior; clinically proven 95 percent effective Remove cap, screw on diffuser, and plug in; replace bottle every 4 weeks and diffuser every 6 months Odorless and non-toxic; does not affect humans or pets; not a drug or tranquilizer; use for 90 days for best results Comfort Zone with Feliway helps to end urine marking and scratching