WThe type of RF signal blocker or any other types of jamming devices you have to choose when it comes buying a blocking devices depends on the couple of things. First of all you have to know how much money you are willing to spend on such purchase and of course make sure that you have saved them. The next thing is to make a list with all of your needs and therefore look for the device that can meet your requirements.
It seems a tidy solution, however, there's a problem. cell phone jammer are illegal in most countries, except to military, law enforcement and certain governmental agencies.