Aerostar 20x20x1 MERV 11 - 4 Count - Pleated HVAC, Furnace & Air Conditioner Filters - Removes Dust, Cold & Flu Germs, Lint, Mold, Pet Dander, Allergy-Causing Pollen, Smog & Smoke JOISTOON the opening on the lid

the opening on the lid can protect your wires form damage by sharp edges

Nuts and bolts are included for the installation

ANSI compliant when worn in the forward and reverse donning positions

2 sets x hanging racks

use for wardrobe / closet dividers

Aerostar 20x20x1 MERV 11 - 4 Count - Pleated HVAC, Furnace & Air Conditioner Filters - Removes Dust, Cold & Flu Germs, Lint, Mold, Pet Dander, Allergy-Causing Pollen, Smog & Smoke JOISTOON the opening on the lidBrand: Aerostar Color: MERV 11 Features: Nominal size: 20x20x1; Actual size: 19 3 4"x19 3 4"x3 4"; This MERV 11 filter is comparable with MPR 1000 1200 & FPR 7 Designed to filter microscopic particles such as lint, dust mites, spores, pollen, pet dander, fine dust, and smoke Simple to install and a cost effective step towards a healthier home environment. For best results, change your filters every 60 to 90 days but increase frequency to 30 days