RFID Technology eliminates the need for line of site reading. It can penetrate body tissue, wood, plastic, mud, manure and more. Allflex RFID tags are passive, meaning that it requires no battery and will last the life of the animal. The passive RFID devices have read ranges from a few inches up to 18 inches. The information is never kept on the tag; the information is stored using your farm record keeping systems. This RFID technology allows for easier management of herd data as well as for animal tracking through the NAIS System.