3-1/4 in. D X 3-1/4 in. D 90 deg Galvanized Steel Wall Stack Elbow, Imperial Mfg, Mfr#: GV0060-C

For all heating air conditioning and venting where rigid pipe is required. The 3 1/4 x 10 90? galvanized flat (shortway) elbow is used to make 90? in your stack run.