120 film is still a very popular medium format film, especially with the recent popularity of the Holga. The 120 film format was originally introduced by Eastman Kodak for its Brownie No. 2 in 1901. The 620 roll film was the same size, but didn’t have a spool and is discontinued.
It was the main format for amateur photographers and beginners’ cameras like the box cameras. With the popularity of 35mm 120 film became a format for professionals.