A big hats off to Federer! This autographed Roger Federer hat is a fantastic addition for the tennis memorabilia collector. This tennis icon has won 16 Grand Slam singles titles, is one of seven male players to capture the career Grand Slam, and one of only three to do so on three different court surfaces: clay, grass, and hard. Many sports analysts, tennis critics, and former and current players consider Federer to be the greatest tennis player of all time.