Tennen OnSen aka. Natural OnSen is Tennen's first album, first distributed in The Voc@loid M@ster 7. It features KAITO, Hatsune Miku, Kagamine Rin/Len and Camui Gackpo as the vocals and consists of 15 tracks; the most famous one being Hai wa Hai ni, featuring KAITO. （*・ω・）waoonP also participated in the mixing, while the design of the label on the album cover belongs to Itaru.