These are very comfortable and light.  They come with a 3.5mm plug and a 1/4" adapter to fit into most MP3 players, computers and keyboards.  They seem to be well constructed, especially for a pair that cost just over $10.  The sound is good but I think that while the mids and bass are great for a headphone of this price range, the highs are a bit too bright - even harsh - for my overall preference.  I must admit that I have a $1299 pair of HiFiMan Edition X V2's that I normally listen to so it's not a fair comparison.  I use these Yamaha's to listen to music and audiobooks when I'm on my treadmill and they do just fine.