Standard size #641R6 register boxes are lined with 1-1/2 in duct liner to provide an R-Factor of R-6. The #641R6 register box is 4 in H with snap rail flange.
M&M Insulated Register Box, Series: 641R6, 5 in Collar, 8 in Length, 5 in Width, Steel, Galvanized
- 4 in tall