Get ready for f(x)'s "4 Walls" because they will perform the song for the first time on October 29 on 'M! Countdown'!

That's right.  The song will performed for the first time on this music program, after which they will perform on 'Music Bank' on the 30th and 'Music Core' on the 31st.  

The track will be an elegant and strong EDM track.  Their album will be out on October 27.