EO Tech VM-150/VE-150 tube earphones

In-ear earphones are pretty common these days, and they provide some great sound isolation, but Korean manufacturer EO Tech have upped the ante with the VM-150/VE-150 tube earphones. 
These things slip into your ears like slimy little snakes and provide what EO Tech say is a superior "richness" to your music.  The little earphones measure 15mm and use 6 diaphragms to produce said richness.  They also come in iPod-friendly white!