You are looking at the Nortel P0884002 / PO884002 PFPE-50 Filter for the XA Core system. These units are brand new and the specs are below. Thanks.

Model number PFPE-50

19.53” x 35.90” x 1.88”

White Polyester

Roll Formed Frame

Uni-Grid Support on one side

Unigrid and Polyester Pleated

Two Polytabs