The Fb7 Flak Bike is the oldest military machine still in use by the Agurts forces, it is the first transformable vehicle developed after the nuclear end to WWII.
The first of the 2 forms employed by the Fb7 include a bike piloted by a single operator with open space at the rear for additional personnel or haulage. In bike mode, the Fb7 has no weapons and offers little protection, it's heavy tracks and bulky frame may affect speed but enable the vehicle to continue operation in a hostile environment and travel over rough terrain.
The alternative form of the Flak Bike is to deploy into a large long range artillery cannon. These cannons can deal devastating damage to enemies at considerable range. Both an offensive and defensive weapon, they operate best when deployed in numbers, taking formation and raining shells onto enemy fortifications, advancing vehicles or closely packed infantry squads. The effects of the Fb7's fire causes low morale in enemy troops who may receive heavy casualties before getting the opportunity to retaliate.
The transformation process for the Fb7 is different to other vehicles and mechs in the Acid Rain World, the operator must leave the vehicle (therefore relinquishing what little protection is offered), press a button and standby as the vehicle changes form. An advantage of this vehicle is that it can be operated remotely, it does not need a pilot to move it towards a shooting point.
Flak bikes are considered old fashioned in the new age of armour development but they are still found in use in Agurts and Zamaii. As they are developed to concentrate on ranged bombardment, close combat and fast support is required for protection against nearby enemies. In the Acid Rain World story, there are a number of deployed Flak Bikes in the background when King receives Damien's letter explaining Bob has been killed. After reading the letter, the monotonous blasts of the cannon fire sounded to King like a tribute to a true hero.
The Fb7 was first shown as a prototype in the 3rd quarter of 2014 in bike form. It was piloted by a figure similar to Bob when wearing a gas mask and infantry style helmet. A second prototype was displayed at Hong Kong Toy Soul 2014 deployed in mobile cannon form. Whether the Flak Bike and it's pilot will be released in Sand or Marine remains to be seen, the final version is expected in 2015.