Can use cell phone signal blocker for schools

We have nothing against people who use their usual mobile phones, if they speak in a normal tone and do not scream loudly, but this damn continuous beep is as annoying as being bitten by mosquitoes and listen to the other end of the conversation that is usually returned (REAL LOUD is simply unbearable

In Perfectjammer.com have a great desktop model of cell phone jammer for schools which you can use in your classroom