A hubcap, wheel cover or wheel trim is a ecorative disk on an automobile wheel that covers at least a central portion of the wheel. Cars with stamped steel wheels often use a full wheel cover that conceals the entire wheel. Cars with alloy wheels or styled steel wheels generally use smaller hubcaps, sometimes called center caps. A wheel cover is also an accessory covering an external rear-mounted spare tire (also known as a spare tire cover) found on some 4x4 vehicles.