Release Date: May 17, 2017

Contents of the package:
- 1 CD
- 1 Photo Book
- 1 Photo Card (random out of 27 types)
- 1 Special Photo Card (random out of 9 types)
- 1 Photo (random out of 3 types)

[Track List]
- SIGNAL
- 하루에 세번
- ONLY 너
- HOLD ME TIGHT
- EYE EYE EYES
- SOMEONE LIKE ME

The 4th mini album "Signal" by Twice features a variety of tracks including the title song "SIGNAL" and "SOMEONE LIKE ME."