Fantech FEL 4 Low Profile Plastic Elbow, Fits in 2" x 4" Wall (411056), 4"

For a 4-inch duct. Heavy-duty plastic 90º mounting collar/elbow for use in 2×4 stud walls. With half-inch drywall lip already set, just nail in place and connect duct. Low depth profile makes this elbow the perfect solution for sidewall ventilation within a wall partition