Let me preface the design discussion by saying that this headphone may very well have come out of the same Chinese factory that makes very similar-looking wireless earphones for other online-only brands like TaoTronics, so it's hard to call these truly original or special.
That caveat aside, the SoundBuds Slim earphones do have a simple elegance to them and seem sturdily built with metal housings and a fairly thick cord. They're also sweat resistant and come with a basic carrying pouch for storage. Battery life is rated at 7 hours at moderate volume levels, which is fairly decent for this type of headphone.
The most important thing for me was that they fit well and worked reliably with minimal Bluetooth hiccups. They come with four different-sized silicone eartips and three different-sized sports hooks to help lock the bud in place. The larger tips and hooks allowed me to get a secure, tight seal, which is crucial to maximizing sound quality.
The cord may be a little short for some people but it was fine for me, and the buds are magnetic, so you can wear the earphones around your neck like a pendant when you're not listening to them. The USB charging port is in the inline remote, which is where the microphone for making calls also lives.
For their low price, SoundBuds Slim deliver good sound and I think most people will be satisfied, but I wouldn't say they sound great and they're only OK for making calls. The bass is a little loose -- by that I mean it's a little boomy -- and the treble has a touch of a harsh edge to it.
The way I dealt with those issues was to lower the volume, but if you like to play your music loud, this may not be the headphone for you. However, those of you looking for a decent set of cheap wireless headphones for both gym and everyday use, the SoundBuds Slim are a good choice and my current favorite Anker Bluetooth headphones.