There were many different type-of phasers mounted to starships.
After the completion of the dominion war, in the late 2370s, Starfleet Security updated the sights of the type-III to a red holographic style allowing for great accuracy and target acquisition. The Starfleet phaser rifle, also known as the Type 3 phaser, was a rifle version of the Type 2 phaser. Type 1 phaser is a small concealable sidearm weapon.
This was the armament of choice for many of Starfleet's larger vessels and some of its medium-sized but patrol/combat-oriented craft. Phasers in the process of overloading emit a distinctive high-pitched whine.