The Honeywell 203369 is the correct replacement pre-filter for the following air cleaners:
The Honeywell 203369 Pre-Filter 12.5x20x.375 2-Pack is a replacement pre-filter for the Honeywell model F50 and F300 air cleaners. This Honeywell air filter traps larger particles in your air to help improve your overall indoor air quality and increase the efficiency of your Honeywell air cleaner. This Honeywell pre-filter arrives in a two pack for your convenience.
Honeywell 203369 Pre-Filter 12.5x20x.375 2-Pack specifications: