Cobalt Sky

 is the fourth single by Aoi Eir.

CD

 * 1) Cobalt Sky (コバルト・スカイ)
 * 2) DAY BY DAY
 * 3) Saishoku no Hoshi (彩色の星)
 * 4) Cobalt Sky (コバルト・スカイ) (Instrumental)

Limited Edition A DVD

 * 1) Aoi Eir “BLAU TOUR 2013” 2013.3.15 at 赤坂BLITZ

Limited Edition B DVD

 * 1) Cobalt Sky (Music Video)
 * 2) Making of "Cobalt Sky" in Oshima
 * 3) Document of Sakura-Con in Seattle