Summary: The earbuds construction are good but the battery module is in the wrong place because is to heavy to carried in. When you turn in the noise cancelling it make a "shhhhhh" noise and I really think don't cancell any external sound. I have to useit like normal earbuds because this sound. I don't recomend this product.
Summary: These are the best noice-cancelling headphones I have found for the price range. I like that they are small and easy to pack so I can use them on a plane. The sound quality is good and the battery operated noice-cancelling works well. It doesn't get all the noice, but does dampen it quite a bit.
Summary: The active canceling on these require a AAA battery, though will function in passive manor if the unit is not turned on; in other words, the headphones will still work and reduce noise (somewhat) without a battery. I've been very happy with the battery life thus far. I didn't time it exactly, but my mp3 player usually gets maybe 15 hours on a single AAA and I changed its battery well before I changed the ones on these headphones.
Summary: this is a great deal: 2 for the price of one!my only reservation about these is that they claim to be 70% noise cancellation. I have tried other products which claim to be 70% NC (more expensive, of course) and these don't really match up. maybe closer to 50% NC. however, for the price, you can't go wrong! they cancel enough noise for what you're paying for!