WAN★OPO! THE BEST OF BEST (ワン★オポ! THE BEST OF BEST!!) is Wonderful★Opportunity's first major album, featuring their most notable works. It is a compilation album consisting of 18 songs, featuring exclusively Kagamine Rin and Len. The official website can be found here, a crossfade can be seen here. The album can be purchased on amazon.co.jp and cdJapan.