First Division B is a professional football league in Spain that operates as the second tier of the Spanish football league system. It was established in 1929 and has undergone several name changes, with its current title being used since the 2016-2017 season. The league features teams that compete for promotion to the top tier, La Liga. The league typically consists of 22 teams, with each team playing 42 matches in a season. The top teams at the end of the season earn promotion to La Liga, while the bottom teams face relegation to Segunda División B. The competition is known for its passionate fan base and competitive matches.