Register boots with flanges, can be used in the same manner as a universal register box. The universal register box has been developed with a flange around the mouth (outlet) of the product. The flange serves several different purposes, including a sheet rock frame with area for register screws and nailing area for joists. Ability to install box before dry walling."}},"base-catalog-100208569":{"__typename":"BaseProduct Galvanized steel construction Always seal seams with building code approved sealant or duct tape Install with sheet metal screws Always insulate ductwork for greater system efficiency and comfort