Oh difficult ~Sonar Pocket×GFRIEND

 is the 32nd single released by Sonar Pocket. The lead track features K-pop girl group GFRIEND.

Regular Edition CD

 * 1) Oh difficult
 * 2) SUN of THE SUN
 * 3) TOP OF THE WORLD
 * 4) Oh difficult (Instrumental)
 * 5) SUN of THE SUN (Instrumental)
 * 6) TOP OF THE WORLD (Instrumental)

Limited Edition CD

 * 1) Oh difficult
 * 2) SUN of THE SUN
 * 3) TOP OF THE WORLD

Limited Editions DVD

 * 1) Oh difficult (Off Shot Movie)

Featured Members

 * ko-dai
 * eyeron
 * matty
 * Sowon (track 1)
 * Yerin (track 1)
 * Eunha (track 1)
 * Yuju (track 1)
 * SinB (track 1)
 * Umji (track 1)