Installation 03, also known as Gamma Halo to the UNSC, is one of the seven massive Halo Arrays built by the Forerunners. It is also the third Halo installation to be discovered by humanity. Installation 03 is located in the Khaphrae system, and was managed by its Monitor, 049 Abject Testament. Alongside 049 Abject Testament, another Monitor, 859 Static Carillon acted as keeper of the Composer's Forge, a facility located off-world but accessible via a portal on the ring.