Five quick inputs, then a set of matches — the same size, cut, and color logic described in the product design doc, running here against live eBay inventory.
This now calls eBay's live production Browse API — these are real, currently-listed items, not samples. eBay is a marketplace, so condition (new with tags vs. pre-owned) and exact color varies listing to listing; the size crosswalk is confirmed where a listing's title states it plainly, and shown-but-unconfirmed otherwise.