DUST BOX is the seventh doujin album by PolyphonicBranch, published at THE Voc@loid M@ster 20. It contains 6 tracks sung by both Miku and GUMI and a bonus track sung by the utaite Hanatan. Album's official page is located on PolyphonicBranch's website and the crossfade can be viewed on Nico Nico Douga. It can be ordered through Amazon.