(TrendHunter.com) CASETiFY and BTS collaborated on a collection of tech accessories inspired by a hit summer song from the pop icons. Based on the number one Billboard song, Butter, the collection is full of design... (TrendHunter.com) CASETiFY and BTS collaborated on a collection of tech accessories inspired by a hit summer song from the pop icons. Based on the number one Billboard song, Butter, the collection is full of design...