The Io-class light cruiser was class of light cruisers used by the UNSC during both the Insurrection and the Human-Covenant War. The ship was designed as part of the UNSC's military rearmament program along with the Hades-class heavy cruiser. At the time it was considered a top-of-the-line warship armed with a new heavy coil Magnetic Accelerator Cannon and twenty-six archer missile pods. The Io-class was well liked by the Navy who found to be well-suited for patrolling and economically appealing. When the Halcyon-class was introduced the Navy still preferred the Io which for every Halcyon they could build four. They were deployed in great number during the Eridanus II Insurrection where they assisted in combating the Insurrectionist's fleet.