ACCO or Acrylic Cervical Occipital Anchorage is an appliance in field of orthodontics which is used for molar distalization of maxillary molars. This appliance is a removable type of appliance which was developed by Herbert I. Margolis. This appliance is intended to be worn 24 hours a day except during meals. It is one of the few removable appliances made for distalization of molars and thus require patient compliance for the treatment to be successful.[1][2]