Monster has created several Adidas-branded headphones and this wireless in-ear sports model, the $100 (£90; AU$150) Adidas Sport Adistar, is a particularly good one.
This is a noise-isolating headphone, which you means you have to jam the tips into your ears to get the best sound. If you don't get a seal, you lose a lot of bass, and the sound will come across as thin. But one of the key design features is Monster's SportClip wings that lock the bud in place and help create a secure, tight seal.
I did a couple of runs with these headphones and they worked very well, with a stable Bluetooth connection for the duration. I had to to make minimal adjustments as I ran and the cord length is easily adjustable with the integrated cord shortener.
A couple of caveats. I'd have preferred if they were rated as waterproof (and washable), not just sweatproof. Although they held up fine during the week I auditioned them, I can't tell you how well they'll hold up over several months of use. You should also be aware that you won't be able to hear traffic noise if you're playing your music at moderate to high volumes due to their noise-isolating nature.
Like virtually all Bluetooth headphones, this one's equipped with an inline remote and microphone for making cell-phone calls (call quality is only OK). The call answer/end button doubles as as a pause/play button, and if you tap it twice quickly it calls up Siri on iPhones for voice control operation. To advance tracks forward you hold down the volume up button. Hold the volume down button to skip back a track.
Another noteworthy feature is the dual battery design (presumably one in each bud) that boosts battery life to as much as eight hours, depending on the volume level. And I liked how you charge the battery through a Micro-USB port in the inline remote, where the electronics live, rather than the bud. This is a new design feature for wireless in-ear headphones for 2016 and you'll find it in several models later this year, including the Sol Republic Relays Sport Wireless and Jaybird Freedom.
Monster also makes the Monster Clarity HD Wireless for $20 less. It's the same headphone but doesn't come with the SportClip wings and ships with a different carrying pouch. But the two headphones sound the same.
As long as you can get a tight seal, the Adistar's sound quality is quite decent though not exceptionally good for Bluetooth. The headphone offers strong, fairly tight bass and reasonable clarity up to about 75 percent volume. But it distorts a bit when you push the volume to the top, especially with more complicated tracks that have a lot of instruments playing at once.
The headphone sounds a little bright -- the treble's a little hyped and that leads to some sibilance and potentially a harsh edge when listening to tracks that aren't recorded very well, which unfortunately applies to a lot of today's music.
I compared this to the Jaybird X2 and I thought the Jaybird sounded a little smoother and more natural, but I got a better, more comfortable/secure fit with this Monster. The Adistar's earbud is smaller and didn't create any pressure points like the X2 can.
I also put it up against the Beats Powerbeats 2 Wireless. The Beats sounds slightly better as long as you get the right fit, but I prefer the design of this Monster and found it easier to slip in and out of my ears (I always have to fiddle around with the Beats to get the right fit).
Finally, it's worth mentioning that I've also tried Monster's earlier iSport wireless in-ear headphones and this model is superior to both the standard iSport Wireless and iSport SuperSlim.
In-ear sports headphones are very difficult to do. I still haven't met one that combines a great fit with great sound. Monster's Adidas Sport Adistar gets it about 85 percent right. The fit is excellent for an in-ear sports headphone, battery life is decent, and the included Sport Clip wings really keep the buds in your ears.
If you aren't a stickler for sound quality, you'll think the sound is quite good and a clear step up from sub-$50 in-ear wireless headphones. But anybody who's used to a decent pair of in-ear wired headphones will be more critical of the sound, especially at higher volumes.
That small knock aside, for the price this is a better deal than competing wireless sports models from Beats and Jaybird. It's a shame it doesn't cost $80 like the Monster Clarity HD Wireless does, but there's a price to be paid for wearing the Adidas logo.