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, 25 in Width, 3-1/2 in Height, 30 ga Gauge, Steel, Finish: Galvanized
- Length 20 in
Specification Sheet- R4 and R6 return air duct board insulation
- Flanges for direct connection to grill
- Easy attachment to duct with start collar