These are truly awesome earphones. They effectively block out background sound w/out forcing you to blast out your eardrums. The sound quality is very clear w/surprisingly good bass for such tiny speakers (I listen to a lot of electronica w/pounding beats so good bass is essential for me). Handles more delicate classical music well too. Also, they are super-comfortable and lightweight- ideal for endurofest rides and runus. The extralong cord is nice but can get tangled a bit too easily
Sennheiser made these earbuds specifically for the active ones out there. They are sweat resistant and fit perfectly into your ear via anatomical design. And they're green. Which is always better.
Perfect for impromptu filtering of annoying chatter from the cubicle next to you, the booming beat of your downstairs neighbor's techno album, or napping on airplanes.