The Remington 7 Shot Fluted Aluminum Magazine Expansion is used to increase capacity to 7 shots for Remington 870 12 gauge shotguns. It holds an additional two 2.75" shotgun shells. It is constructed of military type III anodized, 6061 T6 aluminum making it virtually indestructible. This magazine extension requires a minimum barrel length of 18.5". It includes the magazine spring and the Magazine Extension Swivel Stud Cap.