As we know, as smart devices become more and more popular, it also causes children to have worse and worse access to them. However, long-term use of smart devices can have a serious impact on a child's vision. So, in order to avoid premature myopia in children, the child protection association commissioned a research institute to develop a cell phone jammer. Such devices can effectively prevent the transmission of mobile phone signals. You don't have to worry about your child staying up late at night with his or her phone