these be not really noise canceling , but noise cover headphone . the `` noise cancellation '' feature really just generate some white noise and boost the volume a little . they trick you ear into block out certain frequency . I doubt they work as well as bose 's $ 300 headphone , but for as cheap as they be , they be a steal . I work in a office where people be addict to speakerphone and turn they conversation up so that I can hear every word clearly . I be a computer programmer and it be a bit difficult to work with 4 different conversation blare in my ear . I use to have regular headphone and would turn they up to drown out the noise -lrb- bad for eardrum -rrb- . with these , I can turn music on a low volume and can not hear a thing ! the sound quality be not so good and they smell like new plastic for the first month , but they be cheap and cancel noise well . also , they be collapsable and come with a battery and a nice little carry case so they will not get scratch when you be travel .