16x25x4 MERV 8 White-Rodgers Air Filters - $18.50/ea.
Amazon.com: Filterbuy 16x25x4 Air Filter MERV 8 Dust Defense (4-Pack), Pleated HVAC AC Furnace Air Filters Replacement (Actual Size: 15.38 x 24.38 x 3.63 Inches) : Tools & Home Improvement
Amazon.com: Honeywell Home 16x25x4 MERV 8, AC Furnace Air Filter, 3 PACK (CF408F1625-3PKAM) (Actual Dimensions: 15.63 x 24.75 x 4.38 in.) : Everything Else
Amazon.com: Honeywell Home 16x25x4 MERV 8, AC Furnace Air Filter, 1 PACK (CF408F1625-1PKAM)(Actual Dimensions: 15.63 x 24.75 x 4.38 in.) 1 Filter : Everything Else