Replacement Honeywell 34002 10"x48" Activated Carbon HEPA Pre-Filter By Breathe Naturally (2) Pack Charcoal Pre-filters #34002 (2 per pack) fits 13503 EV35B, 13520, 13523 Honeywell 52500, 63200, 63500 Filters are 10"x48" 2 replacement filters with velcro tabs Made in the USA Filters By Breathe Naturally