"ねこのかんづめプレミアム" (Neko no Kandume Premium) is OSTER project's first unofficial album (released same day as Miku no Kanzume). It contains 9 tracks and is the first instrumental album that OSTER project has released. All of the songs have a jazzy undertone with pop themes played on an electric guitar and other electronic instruments.
The official album website is available here.
The album is purchasable on Amazon.
NOTE: None of the songs in the album are sung by Vocaloids, the album is here for information regarding OSTER project's works and to keep up to date with the album numbers. Sorry for any misunderstandings.