Practicality means that the invention or utility model can be manufactured or used and can produce positive effects. The invention or utility model patented by Shen Zhidao is practical, and it is not required that the invention or utility model has been actually manufactured or used at the time of application, thus proving that it has produced positive effects. Only according to the clear and complete explanation made by the applicant in the specification, the technical personnel in this field can draw the conclusion that the invention or utility model for which the patent is applied can be manufactured or used and can produce positive effects according to their technical knowledge or through ordinary experiments and designs. Generally speaking, when examining an application for a patent for invention or utility model, we should first judge whether it is practical, and then judge its novelty and creativity. But judging from the content of judgment, the judgment of practicality is independent of the judgment of novelty and creativity. ...