As more video consumption moves to mobile, YouTube has a new ad format for brands designed specifically for quick snippets of content.

Today it’s launching Bumper ads—six-second, unskippable video ads—that run before videos, similar to YouTube’s skippable TrueView ads. Unlike TrueView—which lets advertisers create an ad of any length—Bumper caps promos at six seconds, which could force marketers to build campaigns with mobile in mind, since smartphone users have shorter attention spans.

YouTube describes the new ad format as “little haikus of video ads” and will start rolling them out to advertisers this month. Media buyers can buy them through Google AdWords.

Bumper ads are geared towards advertisers interested in testing the difference between TrueView and shorter video clips.

For example, Audi Germany has been testing the ads, and chose to run its original 45-second TV spot revised to the six-second format, with the brand focusing on two shots — one of a soccer player and one of car spinning in a circle.

According to YouTube, early tests with bumper ads are particularly effective when, surprise, paired with TrueView and Google Preferred ads—its premium ads that run alongside the platform’s most popular content from creators.

“Bumper ads are ideal for driving incremental reach and frequency, especially on mobile, where ‘snackable videos’ perform well,” Zach Lupei, product manger of video ads at Google, said in a blog post. “In early tests, Bumpers drove strong lift in upper funnel metrics like recall, awareness and consideration—complementing TrueView’s strength in driving middle and lower funnel metrics like favorability and purchase intent.”

This article was first published on AdWeek.