Excellent, qulaity pair of headphones without cables.

These headphones are exceptional in style, comfort, quality, size and sound; with only two small drawbacks: the size and shape of the wireless transmitter, and the fact that there's little noise canceled.

Sound Quality: These headphones were designed atleast two years ago, yet their wireless sound quality is easily comparable to other blue tooth and wireless headphones; out of the pairs of wireless or bluetooth headphones i own these actually have the best quality.  Most importantly they produce excellent quality sound along the high-frequency range without any static.

Comfort: The gel, around ear support does not put pressure on any part of the ear.  The headphones themselves are not adjustable, but you can turn the around-ear support(s) until the flexible behind-the-neck wire is at a desirable height.  The foam ear-cups do not irritate the outside ear, and the wire is just flexible enough so that the headphones are not too tight on the side of your head and hold in place.  If you take the gel supports off (they're removable), the headphones will just barely hold on to your ears if your head is large enough.

Quality: The clear plastic used around the outside of the headphone's ear cups does not easily scratch or get damaged.  The volume up/down button still works perfectly and is not loose, same with the power button.  The flexible gel (outside) / wire (inside) behind the neck 'wire' is held to the ear cups by (most likely) an aluminum 'clip' that doesn not easily move.
The quality of the wireless transmitter, however, is a bigger issue.  The plastic that it's made of scratches very easily, and the plug has snapped off of my old pair (i bought a 2-year warrantee), damaging my iPod and making the headphones useless in the process.  This, however, did not occur under normal circumstances so i would not consider it a problem with the design.  The plug on my "new" pair is not loose and is held firmly in place.

Size: The headphones themselves are, from what I know, the smallest in their class.  They are not foldable, and i would understand the reason for this design; it increases the life span of the headphones because there are no screws or movable plastic parts, making them more durbale and lighter.

Sound: The sound quality of these headphones is excellent, especially considering the very small size.  I have no problems when listening to high frequency tones, or any music in general.  I was surprised to find out that these headphones have a 'bass boost' option, which again is exceptional considering the size.  One problem with these headphones is that they cancel very little noise; if you're in a noisy, crowded area you will hear people around you.  The high volume capabilities compensate for this issue.  I will also mention that the range of these headphones (33ft) is true as advertised.  I can hear music perfectly from certain areas on the first floor of my home when the iPod is on the second floor.

The Wireless Transmitter:  The problem with the transmitter is that it was originally made to fit with the iPod mini; when used with it the depth of the transmitter is exactly the same as depth of the ipod (.5 in.).  I have recently opened the transmitter, and noticed that there was PLENTY of wasted space; I was dissapointed to see that the headphones were designed so well, yet the transmitter designed poorly.  I noticed the transmitter could be reduced in all dimensions (length, width, depth), and it would definitely be possibly for logitech to re-design the transmitter to better fit with newer iPod models.  Other than that, it's perfectly fine.