Iconic Oakland Athletics New Era fitted hat done up in Green and Yellow with a Kelly Green under brim, White inside lining, and 1989 Battle of the Bay World Series Side Patch. The Bay Bridge Series, or the Battle of the Bay, is the name of a series of baseball games played between—and the rivalry of—Major League Baseball's Oakland Athletics of the American League and San Francisco Giants of the National League. The series takes its name from the San Francisco–Oakland Bay Bridge which links the cities of Oakland and San Francisco.
