Also found in WORLD SERIES HATS New Era Oakland Athletics Authentic Collection 59FIFTY wool fitted hat by New Era. 'WORLD SERIES CHAMPS' has kelly green crown and gold visor, throwback kelly green undervisor, raised embroidered team logo on front, 1972 WORLD SERIES embroidered patch on side . These WORLD SERIES CHAMPSs are authentic Oakland Athletics baseball caps made by New Era for official MLB - Major League Baseball teams.