The B04-BIRDIE2 is a booster part that appeared in Armored Core: Nexus and later in both Armored Core: Nine Breaker and Armored Core: Last Raven
Part Description
BIRDIE model redesigned to offer improved boost power.
Acquisition
This part can be purchased from the shop for 86,000c. In Last Raven, the part is hidden in Eliminate the Enemy AC.