Secure, online ordering, and to-your-door-delivery - it's a snap to order Honeywell-compatible pre filter # 190910.
NOTE: Some of Honeywell's F52D series models use a different size - # 198442, measuring 19-1/2 x 26-3/8 x 1/4. MEASURE YOUR EXISTING PRE-FILTER FIRST!!
Approximately 19-1/8 x 27-3/8 x 1/4
Honeywell F52D Series; F52D1001 (pre 1983)