Question: what is the difference between nct u and nct 127?
Answer: NCT U – A group with a rotating line-up, currently consisting of 10 members: Taeil, Taeyong, Doyoung, Ten, Jaehyun, Winwin, Jungwoo, Lucas, Kun, and Mark. NCT 127 – Fixed unit with 9 members from Seoul (127 is the region code), who are Taeyong, Taeil, Johnny, Yuta, Doyoung, Jaehyun, Winwin, Mark and Haechan.