Interstitial ads
An interstitial is a full-screen ad shown between two page views, which the visitor closes to continue to the next page.
How it works
Interstitials appear at a natural break in browsing: after the visitor taps a link and before the next page shows. The ad fills the screen, so for a moment it has the visitor's full attention, and then it is closed. The creative does all the work: the offer must be readable at a glance, on a phone held upright as well as on a desktop screen.
A full-screen interruption costs the publisher some goodwill, so interstitials run under strict frequency limits. Each visitor sees few of them, which keeps reach per person low and attention per impression high.
Example
At a $1.20 CPM, 80,000 interstitial impressions cost 80,000 / 1000 × $1.20 = $96. If 160 people install your app, the cost per install is $96 / 160 = $0.60.
On UluMob
Interstitial campaigns are billed per thousand impressions (CPM) from a default floor of $0.20, with a $15 minimum daily budget. Upload a 1080×1920 image for mobile and a 1920×1080 image for desktop. The close control must stay visible; creatives that hide it or imitate a countdown trap are refused in review. The format suits mobile offers such as games, apps and value-added services (mVAS).