The document is a mobile phone security advisory from Xinmin Secondary School for parents. It informs parents that while the school tries to ensure security, mobile phones do get misplaced, lost or stolen. It provides 10 tips for parents to better protect their children's mobile phones from theft, such as only allowing inexpensive phones to be brought to school, purchasing security software to track lost phones, reporting stolen phones to police with IMEI numbers, and how to check if a used phone was stolen using the IMEI number on the HITS system website or SMS service. The advisory is signed by the Head of Discipline at the school.