VOCAROCK collection 4 feat. 初音ミク is a compilation album by FARM RECORDS. It contains 20 tracks written by various producers. Notable songs such as kemu's Invisible, 1640mP's Torinoko City, and Nem's Kaitou Peter & Jenny are featured.
This album features GUMI, Miku, Rin, Luka, Len. It's also the first "VOCAROCK" series album to feature a 1st Place Co., Ltd. Vocaloid: IA.
The official album website is available here.
The album is purchasable on Amazon.