It's a throwback with SNSD's Sunny, SooYoung, SeoHyun, TaeYeon, Yuri, and the singer/songwriter named Saara.
Here's their beautiful photo which was taken at their practice room before~
Release Date: January 17, 2017
Release Date: June 28, 2016
Release Date: December 10, 2016
Release Date: May 17, 2016