Subtle At First, But They Really Make a Difference.

I would describe aircraft noise as a combination hiss, hum and roar. The PXC 250 headphones do not remove it all, but they knock out the roar, leaving only the far less fatiguing hiss and hum. And once you turn on some music, the hiss and hum disappears. They worked well mid-plane on a 767 (19A) as well as in the back of a 757 (35A). They make air travel far less tiring.

I enjoyed them on the airplane, with my Dell Jukebox 20. The sound is good, though bass is not strong at low volume. Bass improves with volume, which is to be expected. They got loud enough to drown out the crying baby in the seat behind me. They were also an asset on the train, though the train is far less noisy than an airplane. Also good on the treadmill. They reduce the machine noise, and I cranked them up to drown out the daytime television that was on in the gym.

The collapsible headphones fold flat, and pack easily into the nylon zipper case. They are lightweight and comfortable to wear, and I am not a big fan of wearing headphones. The case has an outside pocket for extra batteries or ?

Battery life seems to be adequate. I usually avoid AAA battery devices, but after two trans-continental flights (LAX-NYC) and a round trip Amtrak trip (NYC to Philadelphia) the Duracell Ultra batteries are still working, and show about 70% battery life on the Duracell Powercheck.

The batteries and noise canceling circuit are contained in a black plastic cylinder, about 5 1/4" long by 7/8 inches in diameter. It is light enough to clip on your shirt pocket, or on your waistband while jogging. Two wires extend from the cylinder, one to the music source, and the other to the collapsible headphones. A red LED informs you when power is on.

Adapter jacks for airplane mono and 1/4" phono plug.

The specs, for your convenience:
Closed Dynamic Stereo Headphones
Frequency response: 10 Hz - 21,000 Hz
THD: 0.1%
Nominal impedance: 300 ohms
Sensitivity: 106 dB SPL
Cord: 5.9 ft
Weight: 2.3 oz.
Connector: 3.5mm
Special features: Fold and flip: registered design allows the ear cups to be turned through 90̊ and fold the headphones closed, 1.8 m Kevlar-reinforced OFC copper cable with 3.5 mm jack plug, delivered with an adapter to 6.3 mm (1/4") stereo and 3.5 mm double mono (for airline audio). High-resolution sound due to Sennheiser "Duofol" diaphragms.