After the war with the Zentraedi, the RDF began to design upgrades to its various mecha. The first one completed was the VF-11 Thunderbolt, a replacement for the VF-1 Valkyrie fighter. The new design provided slightly greater speed and maneuverability, increased armour, and better weaponry. The Gun Pod's barrels were doubled to six, to allow for a greater firing rate, and it was the first mecha to make use of a shield. However, relatively few were produced, as the REF's Alpha/Beta design proved significantly more powerful and versatile.