f(x) - 4 Walls SP144 Remix

Copyright©2015 SM Ent.
Remix by Spertz Kum (https://soundcloud.com/new-smu)
Acapella by Kpop Acca-Inst CH2 (https://youtu.be/rUrHMjvTIio)
Original Music Video :
https://youtu.be/4j7Umwfx60Q