21_1/4x23_1/4x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow System/ Trays/ Reservoirs Rootshield Plus is also available

Rootshield Plus is also available in a wettable powder formulation

Features and Benefits: Deep guard design for unmatched performance

BEAM ANGLE: 120 Degree

This thriving colony of Unocladium oudemansii provides protection from pathogens to fruit

Hydrofarm's heavy duty measuring beaker offers easy-to-read

21_1/4x23_1/4x1 Exact MERV 12 Plus Carbon AC Furnace Filters 6 Pack Grow System/ Trays/ Reservoirs Rootshield Plus is also availableNordic Pure Custom MERV 12 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