Return Air Box with Filter Rail Attaches Flex Duct or Pipe to Collar. 16.25 inches x 4.0 inches x 4.0 inches. Holds 16 x 25 filter (not included). Made of galvanized steel to prevent corrosion.Take advantage of the durable 30-gauge zinc-coated, galvanized steel construction of this Master Flow 16 in. Return Air Box to equip your HVAC system with a long-lasting air return box. Opening acts as a convenient connection from return fittings to a ceiling or wall grill (not included) for return air needs. Cut your own opening and install a collar (not included)up to 16 in. Diameter to attach pipe or flexible duct as needed.
Provides collecting port for central return duct. Traditionally used in a ceiling or wall application as an air return chamber, acting as a convenient connection for air return. Compatible with pipe or flexible duct up to 16 in. 30-Gauge zinc-coated, galvanized steel construction provides durability. Accommodates up to 2 in.