This was f(x)’ first comeback stage with Hot Summer. They pretty much nailed it, if you ask me.
f(x) ~ Hot Summer Live@Music Bank 20110617
33MB 3:43 H.264/AVC 480×272 PSP Ready
I watched this on a live stream as it was airing. I had miscalculated the time difference, but luckily I switched the stream on just when f(x) were performing.