Master Flow 8 in. W x 4 in. L to 4 in. Dia Insulated Register Box with Flange R-6

The Master Flow 8 in. x 4 in. x 4 in. Insulated Register Box with Flange provides a transition from round pipe or insulated flexible duct to air register or grill. It is insulated so there is no need to wrap after installations. The insulation also serves as a noise deadener and helps control condensation. It is designed for 6 in. round ducts. The built in flange can be used with Snap on Rails to make installation easier.