I use to have a sennheiser pxc 250 , but it break , so I think to have a try at a different brand . after read all the comment about Sony mdr-nc40 , I think I should give it a try . I receive the item about three day ago , try it on for one day , and it do not work at all . when I use it on the subway , I could still hear the loud noise ; it work like a pair of cheap ear foam filter but more uncomfortable and way more expensive . the headphone be so tight on my ear that it give I a headache . when I be use it on my laptop to watch video , even when I turn on the noise canceling function , I could still hear the loud noise of the tv and my family talk around I ; I end up have to turn up the volume , and eventually change to a pair of normal headphone , which work the same but have better sound quality . I just want something that be light weighted and actually do the job that it say it do , which be cancel noise . this one totally do not work for I at all . not sure if it be defect or simply not work the way it claim . either way , I be return this item today .