Great sound isolation and awesome sound

Overview
Unlike the popular earbuds, these phones don't simply go in your ear. By using expandable sleeves, they are inserted into the ear canal to form an air tight seal in your ear. The result is a design that blocks out ambient noise from your surroundings. The level of sound isolation might completely change your listening experience.

Comfort/Fit
The headphones come with three sizes of both black foam and latex ear sleeves. The sleeves slide on and off the phones with minimal effort.

Both sleeves operate a bit differently.The black foam sleeves are compressed and inserted into the ear. They expand to form their seal. The latex sleeves have a series of three ridges and are simply inserted into the ear. They are flexible enough to form a seal. I personally never liked the latex sleeves, they really never fit very well for me and I found they were not as effective as isolating sound as the black 'foamies'.

Once your phones are properly fitted, they're in there solid. No more getting yanked out by the slightest tug on the cord.

Because of the unique design of this type of headphone your first expreiences might be very unrewarding until you get comfortable inserting the headphones properly. It also takes a little getting used to the airtight seal, if the pressure is off or the seal isn't good, it will feel uncomfortable. It probably took me a solid two weeks before I achieved a good fit with minimal effort.

I have worn these phones for 2 hours at a time and they get a tiny bit uncomfortable, but nothing too bad. I can certainly wear these a lot longer than my old sony MDR-V6s.

Sound
With the sound isolation, you'll hear things you never heard before. I listen to an extremely soft recording of Barber's Adagio for Strings. Parts are so soft I often hold my breath because the sounds of my own breathing is distracting. Unfortunately, I find my own heartbeat gets annoying sometimes! I can listen to this piece on the train, which is something I could only dream of with my earbuds.

Base is strong and crisp, but not overstated like in many headphones these days. At first it was difficult to hearing such solid bass out of tiny little headphones. Mid levels are solid, I do get the impression that the high end is a bit understated.

One thing I notice when using these is the sound isolation means I can reduce the volume dramatically. I rarely listen to songs over half volume because I don't need to. A big plus for those who are concerned with audio levels and preserving their hearing for years to come.

One critical note- wearing these headphones are like wearing earplugs. You will miss sirens, whistles, and other noises designed to warn you of danger. I would not suggest these headphones for use in any environment where hearing these is important. Because of this, I would not recommend these phones be used while cycling or running.

Cord
The phones come with a very short initial cord about 18 inches long plus a longer 3 foot extension. Not sure if there is any way you could use them without the extension, unless your iPod was strapped to the side of your head or taped to your chest. Perhaps a front shirt pocket?

Storage
Shure gives you a very nice looking zipper case which works well.

Replacement parts
Your sleeves will loose their form and degrade over time. So you will have to buy replacements eventually. I've had my phones for 6 months and used them almost daily for 2-3 hours and I have not yet had to replace my sleeves yet, but I estimate I'll be up for a replacement in a couple of months. Replacement sleeves are available from Ebay, Shure's website, or I bought mine from a place called earplugstore.com. They'll run about 2-3 bucks per pair.

Cleaning
You'll be putting these in your ears, so they'll get dirty. Shure does give you a tiny tool for cleaning out the ear wax and dirt.