It was released on November 14, 2017 by Woollim Entertainment and distributed by CJ E&M Music.

The album contains seven tracks, including the lead single, "Twinkle".

[1] On October 30, Woollim Entertainment released the first concept photos & video teasers of members Kei and Seo Jisoo.

[6] On November 14, Woollim Entertainment released the music video for "Twinkle".

The promotion for "Twinkle" started on November 17 on KBS' Music Bank.