The background noise of everyday life can be distracting at best and annoying at worst. It’s hard to concentrate on that audiobook or music playlist when some slick three rows back is slinging stock trades at the top of his voice or shouting at his sales manager. Noise-cancelling headphones mitigate disturbances by determining a baseline for ambient low-frequency sound and producing a wave form exactly opposite of that frequency, effectively cancelling it out. That allows the user to hear only what they want, making for a better audio environment during air travel, at the office, while listening to music, or trying to sleep. If you are in the market for a little peace and quiet, here are three features to look for.