FELIWAY CLassic Refill is the 30 day replacement for your FELIWAY Classic diffuser. Ensuring your FELIWAY Classic diffuser is plugged in at all times ensures that your cat is provided with the safe and secure messages that FELIWAY Classic provides at all times…ready for whatever life throws at them. FELIWAY Classic can help solve behavioural issues such as spraying, scratching, moving house, hiding, changes to their environment (e.g. new baby) and travelling.