新沙洞老虎
"Only U" (; lit. "Because You're the Answer") served as a pre-release single. It was produced by songwriter Shinsadong Tiger, and co-produced by 4Beontaja and Jellyfish Entertainment CEO Hwang Se-jun. Shinsadong Tiger and 4Beontaja arranged the song. VIXX's rapper Ravi teamed up with writer Kim Ji-hyang to write the lyrics.