What do you mean by double filing of patents? Is it more comprehensive? Is it expensive?

It is the same patented technology, invention and utility model that all apply for protection. The utility model examination and authorization is fast, and the invention examination usually takes about 2-3 years. However, the invention patent contains a lot of gold. Once authorized, the protection period is 20 years from the date of application. In addition, the government now encourages enterprises to innovate, and the types of inventions are now funded by the government.