21_1/4x21_1/4x1 Exact MERV 8 Plus Carbon AC Furnace Filters 6 Pack cleanroom HEAVY-DUTY ZIPPER DOOR

HEAVY-DUTY ZIPPER DOOR

and 51F models

as 6-42-12

Trimming and cleanup time are greatly reduced

Overall the knife measures 12-inches

21_1/4x21_1/4x1 Exact MERV 8 Plus Carbon AC Furnace Filters 6 Pack cleanroom HEAVY-DUTY ZIPPER DOORNordic Pure Custom MERV 8 Plus Carbon air filters are made based on the actual measurements so be sure to measure your current filter to get the EXACT dimensions before ordering. As with all Nordic Pure filters, the effective life of your filter depends on the environment in which you live. We recommend changing 1 and 2 filters every 30 90 days. Our 4, 5 and 6 inch thick filters could last up to 6 months. EXACT MEASUREMENT: Furnace and air condition