A Type-VII phaser was a type of phaser emitter usually installed on Federation Starfleet starships.
By the 2350s, Andorian starship classes such as the Thris-class were equipped with a number of phaser arrays of this type. (Last Unicorn RPG module: The Andorians: Among the Clans)
By the 2370s, Federation starship classes such as the Miranda-class were equipped with a number of phaser banks of this type. (DS9 reference: Star Trek: Deep Space Nine Technical Manual)