In recent years, a series of campus safety incidents have occurred, and the construction of campus security has attracted more and more attention from the whole society. Improving the school's safety risk prevention and control system has become the focus of construction. In fact, not only school safety needs to be paid attention to, but also the safety protection of companies, banks and other places is also very important. Economical retractable posts are widely used. However, not all users know how to use retractable posts correctly.
