feliway refil is to be used with the feliway diffuser. Comes as a pack of 3 so will last you for 3 months. It is a synthetic copy of the feline facial pheremone used to mark their teritory as safe and secure. As a results it helps to comfort and reassure them so they are able to cope with challenging situations and to help to reduce stress. it can help and to stop behavioural problems such as urine marking and scratching.