https://www.mossberg.com/category/series/590s/
For the ultimate in shooting flexibility, the all-new 590S Series cycles 1.75″, 2.75″, or 3″ shells. Pick one shotshell length for specific shooting needs, or simultaneously load any combination of those shell lengths. The choice is yours with the 590S.
Full-length stocks are paired with an 18.5″ barrel with bead sight or 20″ barrel with adjustable ghost ring sights and an M-LOKŪ compatible forend.
Compact 590S Shockwave-gripped models come with a choice of 14.375″ or 18.5″ barrels, both equipped with bead sights.