Classical: For Classical, Flamenco and 0-sized acoustic guitars.
Medium Jumbo: For OM, 00, 000, Grand Concert, Dobro, Classic and most other mid sized guitars.
Dreadnought: Specifically made for Dreadnought and similar sized acoustic guitars.
Jumbo: For Jumbo sized acoustic guitars such as J-200, including most 12-string Guitars and Archtops up to 17" bottom bout.
Super Jumbo: Designed for the Super 400 and other large Archtops.