The difference between simulating anti-theft system and digital anti-theft system for books Digital display is used in front panel of control host in digital anti-theft system. And ammeter is used in front panel of control host in simulating anti-theft system. The cover range of digital system is about 2m which is small and it does no harm to our bodies. And the cover range of simulating system is about 12~15m, this system has some influence on our bodies. The power of digital one is less than 6W which is far less than 100W simulating one. Lower power reduces the harm of EM wave to human body from another side. Comparing table of the two systems     Simulating type Digital type Is there a pointer ammeter in front panel of control host Yes No Cover range of EM field (dia.) 12m 2m System power About 100W Less than 6W Stability Bad Good Repair rate High Low Flexibility Low High