Keeping in-ear headphones firmly in place can often be a bit of a problem, especially when you're working up a sweat, so the earpieces on the CX 680 can be fitted with a pair of flexible rubber ‘earfins' that fold inside the curve of your ear and help to keep them secure.

Good sound quality; ingenious ‘earfins' designed specifically for runners

Cables can get tangled; microphone only on CX 680i model

This really is a great set of in-ear sport earphones. The noise cancelation is really good, I used it while biking and on public transportation too - had no issue with outside noise.

Great noise canceling; Sweatproof; Water resistant; Volume control

No mic; No Skip/Play/Previous buttons; Awkward volume control position; Symmetrical cord

These are great for working out or just about any activity, even traveling. Noise canceling feature and audio quality is very good, as you would expect from Sennheiser. Very balanced, with good bass. The ear fins make these impossible to fall out. Well designed product. Would highly recommend.

Sound quality; sport design

Nothing

Weighing in at just 14g these Sennheiser CX 680i Sports are lightweight and compact. The 1.2 metre cable is super thin but still manages to come with inline controls and microphone built-in, so it's perfect for use with your iPhone as well as your iPod.

Ever since my first iPad, I've been using Apple's traditional white earbuds. When I got the opportunity to take a look at Sennheiser's CX 680i Adidas Sport In-Ear Stereo Headphones, I suddenly realized what I've been missing all these years.

Keeping in-ear headphones firmly in place can often be a bit of a problem, especially when you're working up a sweat, so the earpieces on the Sennheiser CX 680 Sports can be fitted with a pair of flexible rubber ‘earfins' that fold inside the curve of your ear and help to keep them secure.

Gym-friendly earphones have typically been referred to as such because they either stay firmly in place or endure physical abuse without immediately dying. And in the past, Sennheiser has made respectable earbuds for exercise, but a new partnership with Adidas takes workout listening to a new level.

Excellent audio performance with strong bass response; Comfortable fit; Stays in place even during intense workouts; Waterproof, sweat-proof.

Some cable thump when running; Neon yellow color won't appeal to everyone.

The Sennheiser CX 680i in-ear headphones are a decent set of not-quite-mid-range headphones with a remote & mic. They're not quite as rugged as we would've expected from a set of in-ears aimed at the gym crew, but their crux fins (the rubbery things sticking up out of the ear buds) definitely help...

I had the opportunity a few months ago to meet Jeff from Hummingbird Media, and had a great talk with him regarding the Sennheiser brand of headphones. I expressed an interest in checking them out, and was pleasantly surprised by the product.

if you run and want an incredible pair of earphones look no further i am an avid runner and have been searching for a long time these sennheier cx 680 hit it out of the park high quality all the way around the sound is astonishing and they dont move once placed in the ear wow how amazing is that buy

Comfortable; Compact; Durable; Good Bass; Good Value; Great Sound; Lightweight; Stylish

Cord Too Short; Without the volume contro