Summary: To start, I purchased these for two reasons. I am a live audio engineer, so I use these for mixing monitors and as my personal monitors when I sing Tenor as part of my group.
These have two speakers per ear. Low/Mid and High. 119db @1mw with an impendance of 21 ohms which means your iphone can drive these quite poorly.
Pros: 26db of isolation, perfect fit for your ears, excellent sound, build quality
Cons: Sibilance when driven hard without proper amplificaiton, 26db of isolaiton