15x18x1 Exact MERV 10 Plus Carbon AC Furnace Filters 6 Pack vacuum Special features of the E-500

Special features of the E-500 includes: the unit works in areas up to 500 cubic feet

Backlit LCD display

• Full spectra to cover the whole grow cycle

Measure EC/TDS

Greensand is recommended for use on lawns

15x18x1 Exact MERV 10 Plus Carbon AC Furnace Filters 6 Pack vacuum Special features of the E-500Nordic Pure Custom MERV 10 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