New Honeywell electronic furnace filters for a F50E system, 2 available. I believe they are new. They measure 16 " X 12-1/2 " X 4-3/8 " deep; 2 are required for 16" x 25" filter size. The model # is FC37iA113. Asking $20 ea.
2 pre-filters model #203371 for the same system. Asking $5 ea
Honeywell: F300E F300E1019 F50A1017 F50A1108 F50F F50F1073 F59A1000, FC100A1011, F50, F300, F52, FC37A1130