For aquatic missions, Gai can equip the Blue Frame with a "Scale System" armor, which has numerous tiny scales that vibrate to propel the mobile suit through the water and can also serve as makeshift shield against phonon maser. With these parts, Blue Frame has higher underwater mobility than ZAFT's aquatic MS but the diving depth is relatively limited, since the mobile suit itself is not built to resist high pressures. Additional sensors such as active and passive sonar have also been installed in the Blue Frame's head. This set of equipment was built by Morgenroete Inc. under Erica's command and serve as payment for employing Gai to complete certain missions. The equipment proved itself in battle on Giga-Float against Gold Frame, in which Gai fought off Rondo Gina Sahaku to protect the installation. The back mounted portion of the Scale System seems to be attached to the suit through the external connector.