The Atalskes phaser IV was a model of directed energy phaser weapon, a hand-held type-2 phaser pistol used by Starfleet in the 23rd century from the early 2270s.
These Atalskes Phaser Corporation phasers were a dual-fire type-2 phaser, with a hand phaser, the Atalskes phaser III, that could be separated from the pistol power-pack grip.
The Atalskes IV was introduced to Starfleet on reference stardate 2/12, and slowly began replacing the older Sestra phaser II units. This was not the sole design used by Starfleet, as the Sestra phaser IIB was later in use concurrently. Phasers of this type were in use by security aboard the USS Enterprise after its refit in the early 2270s.