During the One Year War, the Principality of Zeon military introduced the mobile suit, a new combat weapon for a new type of war. The most heavily mass-produced and most well-known mobile suit model built during the war was the MS-06F Zaku II, and its combat role versatility and easy-to-master controls made it popular among mobile suit pilots. Midway through the war, the Zeonic Company introduced an upgraded version of the Zaku II, the MS-06F-2, or F2-type. The F2 was lighter, making it more fuel efficient and giving it a longer flight time, and it sported an upgraded, more powerful generator. The armor protecting the cockpit was also improved, as well as its overall performance, putting it on a more equal footing with the Earth Federation Forces' RGM-79 GM. The F2 could also be fitted with a pair of solid rocket boosters on its backpack, giving it a very brief but tremendous increase in overall thruster output; this option allowed ground-based Zakus to temporarily become airborne to attack low-altitude aircraft. Though the introduction of the F2 came later in the war, it was used by forces such as the Midnight Fenrir team. After the war, many F2 remained in service - some being retained by remnant Zeon forces waiting for their revolution to restart, and some being captured by the EFF and put to work as aggressor units in squadrons conducting pilot training and mobile suit field testing.
