What Is Love? is TWICE's 5th Mini Album, released April 9, 2018 through JYP Entertainment, featuring the lead single "What Is Love?" It comes in two versions — A and B — each packed with inclusions: a photobook, CD (1 random of 9), 5 photocards (5 random of 90), a scratch photocard (1 random of 9), a clear postcard (1 random of 9), a lyrics book, and a sticker (1 random of 9). The 90-card photocard pool across both versions makes this one of the deeper pulls in the early discography. A limited event photocard was also included in only 300 randomly selected first-press copies, making those particularly rare. The album also has a monograph companion release for collectors looking to complete the full era.