I am coming to realise that iPod/MP3 player earphones take quite a beating indeed. I have owned a number of pairs of said earphones over the past two or three years, and inevitably, eventually they break down (normally the wires get frayed or something, and so you receive audio out of only one ear). The durability of the earphones is compromised also by my habit of wrapping the cord around the iPod itself (apparently a no-no, but I've never found a sufficient convenient alternative).

The Sennheiser CX500 are 'noise isolating' not by using white noise (like the Bose), but rather by fitting snugly in the ear. To this end, a number of ear buds are provided - three sizes of 'normal' round(ish) buds, and supposedly three sizes of 'enhanced' (with an extra ridge) buds, though the package I received seemed to contain one enhanced ear bud of each size (less than useful). (I did send an email to Sennheiser, but heard nothing.) Whilst the noise isolation is not as good as the ruinously expensive Bose Acoustic Noise Cancelling headphones (and that ilk), it is effective, so long as the earbuds fit well (fully in the ear). I use them in the tube and train, and find that exterior noise is muffled, especially when used at higher volumes.

The cord is adequately long - I do not need an extension (I normally travel with the iPod either in my jacket's inside pocket, in my jeans' pocket, or in the side pouch of my backpack). I generally do prefer the type where the cord of one ear (usually the right) goes around the head, so that the trailing lead goes down one side of the body rather than straight down - these are not those type. These are the type where the cord for each ear is of an equal length, and so the trailing cord goes down the chest. That is, however, a minor quibble. Unlike my previous earphones, the Sennheiser 'phones have a volume control on the cord. This is VERY convenient. I use it most frequently when I need to dim the sound when someone is talking to me (i.e. in a shop or on a train). It also allows you to control the volume without taking the iPod out of the pocket or pouch. The range of volume control isn't huge, but it is sufficient (assuming you keep the main volume fairly high, you can't mute the volume from the cord control, but you can significantly reduce it). I am finding that feature a real bonus (though I have read in reviews that it is prone to faults - I've not experienced any yet, touch wood!).

The earphones came packaged in rack blister packaging - clear plastic on cardboard. Breaking into the packaging was indeed a challenge, and, as mentioned, I do appear to have been shafted three earbuds. In addition to the earphones and earbuds, the packaging also contains a little pouch a cable clip (I don't use it) to clip the cable to your shirt or jacket, and a thing around which to wrap the cable (which I don't get on with).