The earphones are very similar in appearance to Apple's headphones. They're white earbuds with a gray rim at the earpiece grille rim. They come with soft foam earpiece covers as well as silicone adapters that make them in-ear. It was difficult to place the in-ear adapters on the earphones, but I'm certain that they won't come off unless I take them off.
In either case, the sound quality and comfort is satisfactory. The advertised frequency range of the stereo earphones is 20-20,000Hz. I tested the frequency response with a series of files from 22Hz to 22KHz. I found that the headphones had a hard time reproducing audio below 50Hz. They could do it, but at a significant drop in volume. They reproduced up to 18080Hz just fine.
It's completely reasonable to use these headphones for any activity you could envision with a backpack or armband because the four-foot cable is long. The convenience of the retractable headphones makes it easy to take them off and on without aggravation.
