13x21_3/4x1 Exact MERV 8 Plus Carbon AC Furnace Filters 6 Pack ph-ec-tds-meters-and-solutions UL-listed waterproof heat mat

UL-listed waterproof heat mat

Data logs direct to your computer via wireless connection with Bluelab Connect Stick

May be daisy-chained together

0-hour REI (Re-entry Interval) & 0-day PHI (Pre-Harvest Interval)

We use a proprietary blend of minerals in our Cal Mag formula to help boost plant yields in fruiting and flowering plant varieties

13x21_3/4x1 Exact MERV 8 Plus Carbon AC Furnace Filters 6 Pack ph-ec-tds-meters-and-solutions UL-listed waterproof heat matNordic 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