13x21_3/4x1 Exact MERV 14 Plus Carbon AC Furnace Filters 6 Pack Monitors & Timers re-calibrate your meters periodically with

re-calibrate your meters periodically with a 20 ml pack of 1000ppm calibration solution

Trim Filtration Options

Precise digital display shows current temps 24/7

This live spore preparation has been developed as a preventative specifically to control common plant pathogens such as Botrytis cinerea

13x21_3/4x1 Exact MERV 14 Plus Carbon AC Furnace Filters 6 Pack Monitors & Timers re-calibrate your meters periodically withNordic Pure Custom MERV 14 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