16x20x4 (3 5/8) Pleated Air Filters MERV 13 Plus Carbon 6 Pack Liquid & Weight Measuring Converts with a switch from

Converts with a switch from sodium to halide

Unique coiled support frame allows for expansion and contraction of the arc tube during operation

favored by thousands of horticulturists—but with the added feature of curved blade tips

Maximum Residue Limits (MRL) and FIFRA 25(b) exempt

It can be used indoors and out on food crops

16x20x4 (3 5/8) Pleated Air Filters MERV 13 Plus Carbon 6 Pack Liquid & Weight Measuring Converts with a switch fromImportant 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. If you are replacing a 4 3 8 depth 16x20x4 filter