• Dynamic stereo mini headphones
• Fold and flip: registered design allows the ear cups to be turned through 90 degrees and fold the headphones closed (headphones will lock in open and closed positions)
• For transport: supplied with soft belt pouch with extra pocket (185 x 105 x 40 mm)
• 1.8 m Kevlar-reinforced OFC copper cable with 3.5 mm jack plug, delivered with an adaptor to 6.3 mm (1/4") stereo and 3.5 mm From Walmart for $149.21
  
  NoiseGard Active Noise Compensation reduces external noise / Foldable - Great for portable use / Includes Belt Pouch
  With all the latest advances in Digital Music and Sound fidelity, should you be using those Headphones that came with your portable MP3 or CD player? Here's a way to get the best possible sound - The Sennheiser Way. The Sennheiser PXC 250 is a closed, dynamic, supra-aural mini Stereo headphone with NoiseGard active noise compensation (requires 2 AAA batteries). Due to their active and passive attenuation of ambient noise, they let you enjoy music even in noisy environments. The headphones are foldable and come with a convenient belt pouch, making them an ideal travel companion. Fold and flip: Registered design allows the ear cups to be turned through 90° and fold the headphones closed (headphones will lock in open and closed positions) Ideal for aircraft and railroad travel High-resolution sound due to Sennheiser "Duofol" diaphragms with spiral embossing 1.8 m Kevlar-reinforced OFC copper cable with 3.5 mm jack plug, delivered with an adaptor to 6.3 mm (1/4") stereo and 3.5 mm double Mono (for airline audio) From J&R for $149.99
  
  Sennheiser PXC 250 Noise Cancel Collapsible Headphones (Silver)
  From Amazon (US) for $169.95 $95.98
  
  

The unit isn't perfect, and it doesn't seal out all noise by a long shot, but when you turn on the music or movies it goes a long way toward helping you forget that you are surrounded by a hundred strangers. You also aren't battling engine noise to hear dialogue. It makes a big difference and it will be going with me on all future flights. I had no problems with pressure or ill feeling, even after wearing it for 4hrs at a time on an int'l flight.

Decent but overpriced! (Rating: 3.00)
Review : I recently got the Sennheiser PXC 250 after a lot of research. This specific product has been very positively reviewed in many technical publications. When it arrived I was impressed at the packaging of the headphones and latter I really enjoyed the sound quality, especially with the noise cancelling active that actually amplifies and colors the sound. The sound cancellation on the other side is minimal....of course mainly in the lower frequencies. What put me off is really the fact that in my third day of use the headphones started having a bad noise when active cancellation is activated. Very annoying! I was hoping for better quality control from this quite expensive headphone that got broke in my third day of use. Yes, they are going for repair....but needed repair so soon??? I wonder how long are they going to last. The design appears cool but the fit and finnish does not appear solid. They make you feel they are going to get damaged soon and not last long.

Plus, the cord is VERY short and definitely limits your listening distances. While the sound quality is really good indeed, it definitely does not justify the retail price these babies are being offered for. If you can get them discounted give them a try... otherwise full retail price is not what they are worth.

Excellent sound, but noise-cancelling causes nauseousness (Rating: 4.00)
Review : After 5 year's ownership of my Sennheiser HD525's, I decided that when I was going to look into noise-cancelling headphones I'd turn to Sennheiser first. The sound-quality of the PXC250 is excellent for a headphone in this size, but I had a major issue instantly with the noise-cancelling feature.

I tested my new headphones out for the first time at work. Sitting in my cubicle I was listening to Nora Jones. It's a great CD to test speaker quality - the voice recording of Nora is clear and precise. The noise-cancelling system worked great in cutting out background noise, but after 5 minutes of enjoyment I became nauseous. I felt this harsh pressure in my inner ear and for some reason it was affecting my balance. I became light-headed and dizzy. I immediately shut off the noise-cancelling system to see if that would help. The pressure in my ears was relieved but I was left with a tenseness in my throat: the same feeling you get with an over-tightened tie around your neck. For the next hour or so I was feeling this pressure in my throat. It was similar to the feeling you get when you want to throw up, but of coarse not that intense.

A year ago I tried on a David-Clark noise-cancelling headset for my private-pilot training. I was impressed with their ability to cancel out noise, but I never felt this pressure in the inner ear. Maybe I did not try them on long enough.

Conclusion is, try the Sennheiser PXC250's out before you buy them. If the noise-cancelling feature makes you nauseous, settle for traditional pair of Sennheiser headphones. For those who do not have the problem I had, buy the PXC250's - I highly recommend them. Their noise-cancelling system works excellent and the quality of sound that these headphones produce lives up to the well-known superior quality of the Sennheiser product line.

light weight, great for air travel (Rating: 5.00)
Review : I travel by air every two weeks and this headset's active noise-cancellation is every effective. I now can truly enjoy listening to my MP3 music without the intrusion of ambience noise even when I get to seat close to the jet engine. It also came with adapter which allows connection to the plane's audio system for watching movies or listening to music. The sound quality is excellent, deep bass and clear trebles. And size is very compact compare to other noise-canceling headphones. The price is also reasonable. The only thing that I didn't like about this headphone is the wand, which houses the battery compartment and the noise-cancellation circuitry, because sometimes it gets in the way.

Great noise reduction, but a little tight and awkward to use (Rating: 4.00)
Review : I purchased these for use on the subway and bus, and for use while I eat lunch outside in the middle of Washington DC. The noise reduction is wonderful, but it's noise reduction, NOT elimination. It's amazing what happens when you turn these off after using them for a while and realize how much noise pollution you haven't been subjected to. They are mostly comfortable, but just a little tight. The cords are prone to tangle a bit, but if you're mostly sitting still while you're using these, it shouldn't be a problem.

I would recommend these for purchase as long as you're not looking for total silence. These are a great way to reduce your stress from noise pollution, and terrific quality for a very reasonable price.

Great quality, REALLY REDUCE BACKGROUND NOISE (Rating: 5.00)
Review : I purchased these headphones about 2 weeks ago primarily to get some peace and quiet at a highly noisy environment at work. I am surrounded by heavy duty computer equipment, printers and a noisy break room. Sennheiser pxc 250 really reduce all the noise to a very manageble level and make it possible to concentrate on my work.
I also used them while waiting in line at the major DMV office (renewing my license). I was really surprised how loud the enironment was, once I took them off.
These headphones are very light and comfortable, there is no ear fatigue at all. The feel a bit light and I was somewhat afraid that I will break them, however, they appear to be very well made. They neatly fold into a supplied case.
I definately recommend them to anyone.
I shopped around, and Amazon has them at the best price.