(Allflex) Allflex Reusable HDX EID Tags utilize Half Duplex Technology. Each tag is printed with the unique ID number that is stored within the tag's HDX transponder. Allflex Reusable HDX EID Tags are made from rigid plastic. Includes Global extended male buttons. Apply with Allflex Universal Total Tagger (remove the clip) or Allflex Retractomatic. 1.28" dia x 0.28" thick.