Fantech FEL 4 - 4" Elbow, Low profile plastic fits in 2x4 wall (411056)
The Fantech FEL 4 is a low profile plastic elbow that is suitable for 24 stud walls.
The Fantech FEL 4 comes with half-inch drywall lip already set in, so you just have to nail it and connect it with the duct. This heavy-duty 90 mounting collar/elbow can be used with 4" ducts. It is ideal for sidewall ventilation within a wall partition.