On this page there’s 4 highlights (view in Baymard Premium) outlining what Costco are doing right and wrong.
(Tip: use the arrows above or on your keyboard to navigate all 566 filtering options examples.)

The screenshot was taken on June 24, 2015 and depicts Costco’s Filtering Options. In total, we’ve reviewed 65 of Costco’s page designs. To see them all, visit the full Costco UX case study.