Wireless networks have one nasty "flaw" – anybody can access it with a little bit of cryptographic knowledge. Yes, security methods have evolved, but they are still vulnerable to people with bad intentions.

 
EM-SEC is a special type of coating that is painted on the walls of your office. It acts like a electromagnetic shield, reflecting all data that is transmitted from your wireless equipment, and containing it inside the room.

 
This sounds perfect, but a few questions still are not answered. What about windows and doors? Or is there some other product for them that we have missed?

 
More info here.