With on-ear headphones, the small ear cushions are placed on your ear. That's why they're also known as supra-aural headphones. Because the ear cushions don't shut you off from the outside world, on-ear headphones are suitable for on the go, since you'll still hear some of your surroundings. Do you often travel by train? In that case, you should get headphones with a closed design, so your fellow travelers won't hear your music.