Fusion boost armors exist for each of the five elements. They are intended for use in enhancing other armors. Each one is worth 180 enhancement points if used to enhance an armor with a matching element, or 150 enhancement points for an armor without matching element. It can be found in Enchanted Chests and obtained by contributing to your guild. In the new Guild Wars update, you can obtain 2 random fusion boost armors by doing the most damage (or defeating) the opposing guild's guardian if their guardian is lvl 7. It is not recommended for combining; it appears to count the same as any other two-star armor for combining purposes.
Use this for level 60 -70 to max out armor.
Because of the high Enhancement Value, using Fusion Boost Armor saves you gold by the reduced use of Enhancement Slots. Enhancement Slots increase in price with the level of the armor to be enhanced, and on higher levels (above level 60) using a Fusion Boost Armor can save you up to 150,000 gold. It makes sense to delay using it as long as possible, because the higher the level of the armor to be enhanced, the more gold it saves you.
Save fusion boost armor to enhance better armor but do not use it on the weak or low level armor.
Found in chests and can be obtained by rewards (guild wars, tournaments, etc.)