16x20x5 (4 3/8) Honeywell/Lennox Replacement MERV 8 Air Filters 1 Pack Tubing The pH sensor in the

The pH sensor in the probe is a single junction electrode with gelled electrolyte and a retractable cloth junction

Roots Organics HP2 is minimally processed to preserve all of the benefits and amazing synergistic qualities found in guano and biogenic phosphate rock

manganese sulfate

Accurate dual-beam CO2 sensor

• Preventative and curative

16x20x5 (4 3/8) Honeywell/Lennox Replacement MERV 8 Air Filters 1 Pack Tubing The pH sensor in theImportant Note: Almost ALL furnace filters have a different "actual size" than the nominal size printed on the air conditioner filter. It's best if you measure your air filter for the EXACT size and compare it to our "Actual Size" and then you can be sure your A C air filter fits! With the 4" and 5" air filters there is a wider variance between the nominal and actual size depending on the manufacturer. We also carry 4 7 8 and 5 1 4 inch depth filters,