This 90° elbow is used to offset around an obstruction.
It is UL listed to standard UL641 as a Type L low temperature venting system. This venting system must be used with appliances requiring this venting standard. Commonly used for wood pellet burning appliances. Galvalume steel outer pipe with 300 series stainless inner pipe. 4" component pieces have 4.75" OD.
1" clearance to combustibles must be maintained when installed.