Choate Tool Fab Arms +3 Shot Magazine Extension Blued. Increase your fire power by +2 shells with our shotgun magazine extension kits. These kits are constructed of solid Matte blued steel and come with spring base clamp & follower. Specifications for Choate Tool Fab Arm +2 Shot Magazine Extension: Manufacturer: Choate Tool Gun Make: FABARM Caliber: 12 Gauge Features of Choate Tool Fab Arm +2 Shot Magazine Extension Adds +2 shotshells machined from steel includes spring follower and clamp Package Contents: Choate Tool Fab Arm +2 Shot Magazine Extension Choate Tool CMT-15-04-03: Fab Arms +3 Shot Magazine Extension Blued