IEM are super comfortable headphones that fit perfectly in the ears. Even when talking or opening your mouth widely, the fit remains excellent. They are very bass-heavy while still sounding clear and detailed at the same time. On a loud stage, even at lower listening levels, the clarity is preserved exceptionally well. The stereo image is wide and transparent, which means the equalizer needs far less extreme adjustment and the natural sound is maintained. As a result, musicians can hear tonal dynamics more clearly and have better control within the mix while being surrounded by other players.
I also love the possibility of having a custom visual design. I highly recommend the UK Audio U11