TAG ABO is the first multiple-configuration tag for ABO and Rh (+/-) identification. You can set your personal blood type information just by threading the cord through one of the eight predominant groups. Wearing it as a necklace or attaching it to personal belongings you will allow others to identify your blood type group in case of emergency. Doctors always will verify your blood type before a transfusion unless it is a critical situation and you wear a blood type ID.