Google this month launched TrueView for reach in DV360. Advertisers now can create line items with skippable in-stream ads optimized for efficient impressions. The difference between the normal true view campaigns is that the bid model is target CPM instead of CPV.
TrueView for reach ads are optimized to deliver more impressions at lower CPMs and to drive greater reach or higher frequency based on your line item settings, says Google. TrueView for reach is available for in-stream ads only.
Bids for TrueView for reach are set based on target CPM (cost per thousand impressions). Some impressions may cost more or less than your target CPM, but altogether Display & Video 360 will try to keep your line item average CPM equal to or lower than the target CPM you set.