This Hi-lo oval stack head with wing is used for transition from oval duct to register or grille and allow further oval duct connection, built-in wings allow for convenient attachment to wall studs. This stack head is available in size for oval duct inlet from 6” to 8”, for rectangular outlet from 10”x 4” to 14” x 6”, and more sizes available for customer request. These stack head are made of 26 gauge galvanized sheet metal up to 12″ or 24 gauge galvanized sheet metal from 14″ to 24″.