Switch-Device Outlet Box Extensions (Metallic): Type - Nongangable; Material - Steel; Number of Gangs - 1; Box Height - in - 3-3/4; Box Width - in - 2-3/16; Box Depth - in - 2-3/4; Capacity - cu-in - 18.5; Clamps - AC/NM Cable; Mounting Hardware - Positioning Tabs, External Nailing Provision