I bought this mono earphone because im deaf in one ear and have always had a problem with headphones in the past where half the sound would be missing and when listening to music it can be very annoying. This earphone can sit on either ear and plays a mono effect sound giving you all the sound into one ear. I am extremley happy with it and for the price have no complaints whatsoever, im sure they're are better ones on the market but you can say that about anything, and how much money do you want to part with? So i would strongly recommend this earphone, the sound quality is good for the price and delivery was very quick.