The room diffuser is a plug-in unit that uses low levels of heat to volatilize the essential oils. Contains diffuser unit and 5 refill pads.The room diffuser is a plug-in unit that uses low levels of heat to volatilize the essential oils.Common Name: Aromatherapy Room DiffuserSimply plug in Aura Cacias Aromatherapy Room Diffuser and, within minutes, you will be enjoying the true aromatherapy benefits that Aura Cacias 100% pure essential oils provide.