23_1/2x23_1/2x1 MERV 13 Plus Carbon AC Furnace Filters 6 Pack environmental You have a choice between

You have a choice between carbon tool steel (the strongest steel available) and stainless steel (rust protection and easy to clean)

25-inch Long

The ROI-E200 is the newest member of the ROI-E series

Drum Extension - 6061 Aluminum

ACTIVE AQUA TITANIUM SUBMERSIBLE RESERVOIR HEATER

23_1/2x23_1/2x1 MERV 13 Plus Carbon AC Furnace Filters 6 Pack environmental You have a choice betweenNordic Pure Custom MERV 13 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