Radio sweeper
Appearance
Radio sweepers are used by radio stations as segues between songs that give listeners a brief station identifier or promo, generally 20 seconds or less: "You're listening to the soft sounds of [NAME] radio. Easy listening throughout the Bay area."
Dry radio sweepers are voice only -- no music or sound effects.
Sweepers are also known as liners, bumpers, radio imaging, sweeps, station imaging, stingers, IDs, promos, shotguns, voice overs, and intros.