ULSR21-ID is integrated two reader modules inside as well as a senstive antenna. this rfid library reader is equipped with metal shileding function to avoid interference from metal, power adaptor, computer, mobile phonte or any other devices that can reflect or transmit electro-managetic wave.For its anti-collision algorithm and strong reading performance, it could reader 6~7 books at the same time to improve the books borrowing and returing effiency. Considerting the electro-magnatic interference around the reader.