Regulations Governing the Handling of Mail Article 26
An international unregistered mail which enjoys preferential handling by the postal services of the destination country and is given to a special courier to deliver as soon as possible and of which the online tracking information is provided, belongs to trackable mails..
中文原文 郵件處理規則第26條
國際非掛號函件，由寄達郵政機構優先處理並交由專差儘速投遞及提供網路追蹤資訊者，為可追蹤函件。