The Master Flow 12 in. x 6 in. x 6 in. 90-Degree Register Box creates a right-angle (90-degree) transition from 6 in. round pipe or insulated flexible duct to a 12 in. x 6 in. air register or grille. This register box is made of 30-gauge, galvanized steel to provide strength and durability. It can be installed with sheet-metal screws.