FILCAB
The filter cabinet is designed for use with upflow, horizontal, and some downflow furnaces. It provides access to a filter external to the furnace blower compartment. The filter cabinet is designed for use with a 4–5/16 in. wide, high--efficiency filter, and is also supplied with hardware to use the 1–in. filter supplied with the furnace

NOTE: An airflow reduction of up to 7 percent may occur when using the 4–5/16 in. wide, high--efficiency media filter. For best furnace efficiency when using the 4–5/16 in. wide media filter, adjust the blower speed tap to near the mid--point of the rise range.

FILCAB = Filter Media Cabinet
X = Shipped with Logos in Carton
L = Long
00 = Factory Assigned:Not Used
20 = Size