An apparatus for automatic radio-frequency identification (RFID). In an embodiment, the apparatus comprises a flexible strap comprising a plurality of holes and a buckle configured to buckle to any one of the plurality of holes, such that, when the buckle is buckled to one of the plurality of holes, the strap forms a closed loop. The apparatus further comprises one or more tag enclosures. Each tag enclosure comprises one or more buckles and a RFID tag configured to communicate identifying data to a reader device. The one or more buckles of each tag enclosure are each configured to buckle to any one of the plurality of holes on the strap such that the tag enclosure may be attached to the strap at any one of a plurality of positions on the strap.