Like the Long Dagger, the Duel Dagger can use a set of add-on equipment known as Fortestra (meaning 'strong dress') to remedy its relatively weak armor and firepower. The Fortestra includes additional armor mounted around the mobile suit's body, providing additional protection against enemy attacks, but it weighs the Duel Dagger down and cuts mobility. To offset this, additional thrusters are included to improve mobility but it is still a problem when the suit operates under gravity. To improve offensive ability, a clip-fed linear cannon and an 8-tube missile pod is mounted on the additional shoulder armor. The Fortestra can be detached if it proves to be burden, and will releases an intense blinding flash so that the Duel Dagger is not vulnerable during the process.