This Master Flow 10 in. x 6 in. Duct Board Insulated Register Box - R6 features R6 fiberglass insulation to help provide high thermal efficiency, control condensation and absorb system noise. The box is ideal for helping you connect round pipe or insulated flexible duct to an air register or grill (pipe, duct, air register and grill not included). It is pre-wrapped and ready to install for easy installation.