Simply 18x20x1 Air Filter, Merv 8, MPR 600, 12 Pack, Furnace Air Filter for HVAC (Actual Size: 17.81″x19.81″x0.75″) DUST, Pet, & Allergy Control

Customers find these air filters to be of good quality and consider them an excellent value alternative to expensive ones. They effectively pick up dust and debris, with one customer noting they do a great job filtering pet dander. While many customers report a perfect fit, some mention issues with inaccurate dimensions.