Atalskes phaser III

The Atalskes phaser III was a model of hand-held directed energy phaser weapon, a hand phaser used by Starfleet in the 23rd century.

History
These Atalskes Phaser Corporation phasers were a dual-fire modification, where the Atalskes III was a type-1 hand unit that was designed to be mated with a type-2 phaser's phaser pistol power-pack grip, with the combined unit referred to as the Atalskes phaser IV. A keypad for the unit's internal computer was located in the joint coupling the two components.

The Atalskes III was introduced to Starfleet on reference stardate 2/12, and slowly began replacing the older Sestra phaser I units. This was not the sole design used by Starfleet, as the Sestra phaser IB was later in use concurrently. 

Phasers of this type were in use aboard the USS Enterprise (NCC-1701) after its refit in the early 2270s. 

Atalskes phasers were among the collection of weapons obtained by the warlord Karnas on planet Mordan IV. Many of Karnas's advanced weapons were obtained through a deal with Commander Mark Jameson in the early 24th century. 

The Atalskes model was in use aboard the USS Enterprise (NCC-1701-C) in 2244. 

Background
This phaser was created for the unrealized 1970s Star Trek: Phase II television series, and ended up being used on the USS Enterprise (NCC-1701) in the movies and The Wrath of Khan. The prop was replaced by different phasers in, but it was brought out of retirement for an appearance aboard the Enterprise-C in "Yesterday's Enterprise", indicating that the model of phaser continued into the 24th century.

Interestingly, while the prop was designed to separate into two units, the hand phaser modification described here was never seen separated from the grip unit in any production or publication.