Ad tech firm Undertone has launched its Expandable Teaser ad format following successful beta testing with clients including BMW and Major League Soccer.

The company said the cross-screen format provides brands with an innovative way to grab attention and drive engagement through great creative that enables consumers to control the advertising experience. The Expandable Teaser format is aligned with the IAB Tech Lab’s LEAN principles.

Built to be mobile-first, but available across devices, the Expandable Teaser format animates a teaser ad above the content of a website, expanding when clicked by a consumer. A content overlay experience with a persistent and non-distracting presence on the page then appears. When prompted, it becomes an expanded canvas for brands to create experiences that engage their target audiences.

“The launch of Expandable Teaser ads continues the evolution and broadening of Undertones product portfolio,” said Undertone president, Rob Schwartz. “With this new format, consumers have more control of the engaging and interactive features that connect them with the advertising experience.”

The IAB Tech Lab released its LEAN Principles – Light, Encrypted, Ad choice supported and Non-invasive ads – in autumn 2015, in an attempt to address the challenge posed by ad blocking, and to encourage the industry to optimise the user experience. These principles were set to help guide the next phases of advertising technical standards for the global advertising supply chain.