The DuraVent 5GWTR4 is an oval increaser tee for your Type B gas vent system. It is designed to attach smaller round pipe to larger oval pipe and is used for a 90-degree offset to combine connectors from the appliances. Measuring 5 x 4 inches, it features the DuraLock system that provides a secure and tight connection. This DuraVent 5GWTR4 is a UL-listed product and is covered by DuraVents limited lifetime warranty.DuraVent has been a technological leader in the venting industry, being committed to provide innovative solutions. Search the one that you need here at PlumbersStock.com.