20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 12 Pleated Plus Carbon 1 Pack commercial-greenhouse-fixtures Each sensor module supports one

Each sensor module supports one temperature and one relative humidity reading

and within seconds the meter recognizes the calibration solution and calibrates itself

(Green = 3

mixing chamber

The material is easy to cut to size

20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 12 Pleated Plus Carbon 1 Pack commercial-greenhouse-fixtures Each sensor module supports oneImportant 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,