SGNL›05 is an EP released by Isis which acts as an extension to their earlier full-length album Celestial, as the tracks were all directly culled from the Celestial recording sessions. Frontman Aaron Turner describes them as being “part of the same whole”, separated from each other because releasing a double album for the group's first full-length may have been overbearing for listeners.

Using the style he pioneered with his work in Godflesh and Jesu, Justin Broadrick reinterpreted the title track from Celestial into a new revision. It is presented on this EP as the closing track, an end to this chapter in the Isis discography considering the epic feel and experimental structure of the reworking that clearly foreshadows the direction the band would eventually take musically. The band has performed a version of the song "Celestial" live several times which fuses the original song and this remix together into a massive 16-minute rendition titled "Celestial (Ext/Alt)" on the Live.02 LP.

In addition to the standard CD and vinyl LP editions, SGNL›05 is available in a combined, deluxe release with its companion full-length, Celestial.