Switch-Device Outlet Box Extensions (Metallic): Type - Gangable 347V; Material - Steel; Number of Gangs - 1; Box Height - in - 3; Box Width - in - 2-1/4; Box Depth - in - 2-1/2; Capacity - cu-in - 16.0; Knockouts/Sides-Ends-Bottom - None - (2)1/2"- None; Mounting Hardware - Plaster Ears, Recessed