Check... https://www.amazon.com/gp/aw/s/ref=nb_sb_ss_i_1_5?k=20x25x4+air+filter&sprefix=20x25&crid=221Z9DA8GERXE ... as Walmart doesn't appear to carry them in store.
Try www.walmart.com and search item. Note about item will tell you if your store has the item.
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