Metal Zinc's Return Air Duct Board Top Box provides an economical way to attach return air grills and return air filter grills.

MetalZinc Duct Board Top Return Air Box, 20 in Length, 20 in Width, 3-1/2 in Height, 30 ga Gauge, Steel, Finish: Galvanized, 1/2 in Flange, Additional Information: R6 Return Air Duct Board Insulation

• R4 and R6 Return Air Duct Board insulation
• Flanges for direct connection to grill
• Easy attachment to duct with start collar
• 30-gauge galvanized steel ASTM A653
• 3-1/2" depth
• Duct board cut and pieced to size

• Specification Sheet https://assets.unilogcorp.com/267/ITEM/DOC/MetalZinc_DBBX2020_R6_Specification_Sheet.pdf
• Specification Sheet https://assets.unilogcorp.com/297/ITEM/DOC/MZ_Boots-Boxes-Stands-0521_6_03.pdf