Which of the following is not a standard ad unit in the UAP?

In the context of the Universal Ad Package (UAP), standard ad units are predefined sizes and formats that are widely adopted across the digital advertising industry. The recognized standard ad units include formats like leaderboards, rectangles, and skyscrapers, which have specific dimensions that advertisers and publishers agree upon for consistency and ease of use.

The leaderboard (banner) is a common format typically placed at the top of web pages. Rectangles can come in various sizes but are mainly utilized for in-content placements. Skyscrapers (or towers) are long, vertical ad units often situated along the sides of web pages.

While buttons were popular in earlier days of digital advertising, they do not adhere to the standardized dimensions or classifications set forth in the UAP. As a result, buttons are not recognized as a standard ad unit under the UAP framework, distinguishing them from the other options provided. This distinction is crucial for ensuring that digital ads are created, delivered, and displayed consistently across different platforms and devices.