Los Angeles, CA (June 6, 2017) Undefeated and World Ranked Featherweight Contender JOSEPH “JO JO” DIAZ, (24-0-0, 13 KO’s), has signed a five-year extension to his managerial agreement with brothers RALPH and MOSES HEREDIA. The Southern California native Diaz represented the United States in the 2012 Olympics in London and he is currently ranked #1 …