Carlson’s Shotgun Magazine Extensions add firepower to your favorite shotgun. These magazine extensions are constructed of blued solid steel and come with spring base clamp and a high visibility follower. The threaded tube replaces you magazine cap and gives you the ability to add extra rounds to you magazine. This magazine extension is compatible with 8 shot Benelli 12 gauge M1 M2 SBE SBEII that use 2.75″ shells.