Now I am twist' turned upside down. I give up, here is the description from Memory Beta, again not canon. Its still a "type-2," but technically made up of a Phaser III and IV.
"In the 2270s, the Atalskes Phaser Corporation phaser IV model of type-2 phaser was introduced, again consisting of a (somewhat larger) hand phaser (known as the phaser III) mated to a pistol handle. These weapons were first issued on reference stardate 2/12 and were used well into the 24th century, despite other models being available. These weapons were used aboard many vessels, such as the Enterprise (from 2273 until 2285), Reliant, and the Enterprise-C."
The above info is from the book I previously talked about.