Invff's 1st Single Album [BUMMER] [Credit] Executive Producer: Invff Executive Visual Director: Hyunseung Ro 01. BUMMER Produced by pilotkid Composed by Invff, pilotkid Lyrics written by Invff Arranged by Invff Mixed by 99db sound Mastered by 99db sound 02. 기꺼이 (feat. Roy Diller) Produced by FAIELO Composed by FAIELO, Invff, Roy Diller Lyrics written by Invff, Roy Diller Arranged by FAIELO, Invff Mixed by FAIELO, Invff, Roy Diller Mastered by FAIELO