The Kicker EB51 headphones are designed in a fashion that is typical for earbuds. The relatively small, round plastic earpieces are hard and smooth and meant to rest just inside the outer ear. There is a rubberized ring around each earpiece that provides some traction for keeping them in the ears. It's a one-size-fits-all design that will not actually fit all. For our part, the EB51 earphones stayed fairly secure in our ears, and the shape of the earbuds proved to be comfortable for about an hour or so of wear. If you wear them much longer than that, the pressure could make your cartilage a bit sore.
Frankly, when it comes to earphones in this price range, we've learned not to expect much in terms of durability, and the Kicker EB510 Stereo Earbuds are no exception. The ultrathin cable gets even thinner at the Y split, and it is not reinforced at the connection points to the earpieces. However, we do appreciate the incorporated slider for reducing tangle incidents and that the plug housing has a bit of extra rubber around it. The cord measures 47 inches in all and terminates in a nickel-plated 3.5mm straight plug.
As for sound quality, it's nothing to write home about; again, we didn't expect much different from a set that runs for around $20. That being said, the Kicker EB51 earphones do not sound atrocious and are perhaps a slight step up from most stock 'buds, though the difference is not as noticeable as with many in-ear sets we've tested. Specifically, bass is lacking with the EB51s, which is a typical problem with earbud-style headphones. Also, music in general sounds pretty thin.
Still, audio is clear with no background hiss or distortion, so you could do worse. And the lack of passive sound isolation makes these a suitable option for those who need to hear their surroundings. In the final analysis, these earphones can add some color to your listening experience and the tweaked shape provides a more secure fit than stock 'buds, but the audio alone is not enough of a reason to upgrade.