Like jabbing two thumbs in your ear canals
Customer Rating: 
A few other reviews have already covered the basics here, so I'll sum it up for you:
Pros
* They stay in your ears
* Lots of bass
Cons
* The band is too big (for me anyway) useless if you want to do any exercise where you're lying on a bench
* You cant change the size of the ear buds, after a while it hurts my ears. Sort of like having two big thumbs jammed in your ears
* Not enough treble/mid range
If you have big ears/ear canals these will probably be excellent, thought not if you have small/normal ear canals. Try running with your thumbs in your ears for 30 mins, then decide if you like how that feels, if you do, buy these headphones.
Must have for runners
Customer Rating: I purchased these headphones over a year ago for training whilst in Afghanistan and they have taken everything in their stride.
They survived three months of harsh weather and searing heat of the desert being used everyday. I use these when I am travelling, in the gym and training at home and have had no problems.
The sound quality is good (I use mine with creative mp3 players muvo and zen), I have played with the eq settings and various music from Rock to dance and chill out and these headphones produce a good sound with no distortion.
These headphones excel out on the roads; I have tried various earphones and headphones over the years and thought these would be no different. They work brilliantly, now I don't have to worry about my earphones falling out and can concentrate on my running.
The downside to these headphones are; there is no adjustment available so when you want to relax with your head on a rest they can get in the way (however if they were made adjustable then this would effect the durability of the headphones) this is a compromise I don't mind taking.
Also I have lost the rubber protectors that fit around the earpieces, I have requested to purchase new ones from the Sennheiser site but still waiting for a reply.
In conclusion these headphones are excellent for runners and are equally as good in the gym, they are sturdy and can work in the harshest environments. They produce a good sound with no distortion that I have found through a year of use. I have and would be happy to recommend them to friends and family.
