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Hardware
1

More or less, at least.

2

Ignoring half the feature list, my Sure SE215 IEM headphones basically never leave my body, I use them for listening to podcasts on my motorcycle all the time.i have never had a headphone I liked more

3

Have you tried the BeatsX? They are a neckband style, though without the clunky horseshoe thing, they’re easy to switch between your paired devices, they have buttons for basic operations. I don’t think they’re IPX4, and they’re not noise-cancelling, though I do find that with the right tips they can be pretty acoustically isolated.

I currently have a two-headphone life with BeatsX for most day-to-day stuff, including phone calls when needed. But for running, I really like the Plantronics Backbeat Fit (an older model that you can still find). They’re rainproof and sweatproof: I actually wear them in the shower after a run to rinse them off. They also have buttons for operation, but I wouldn’t recommend making any calls on it.

In summary, I think that you’re looking for a bit of a toaster-fridge. You might be better served by picking two different ones.

4

You might be looking for the Anker Soundbuds Surge (still my favourites) or the Anker Soundcore SpiritX (noise cancelling isn’t the greatest on the latter though).

Both for a very reasonable price at Amazon

5

I’ve been very happy with the LG Tone headset. I don’t know if it meets all the items on your checklist, but it’s neckband-with-earbuds style, Bluetooth, I THINK it supports two connections at the same time, it’s rainproof (I don’t know what IPX4 is but I have worn it in the rain), it is simple to operate, fingers can find buttons, it has a long battery life, and you can judge the price for yourself.

6

I use the LG Tone also. Only issue with it is the two connections. Unless they have upgraded it, I haven’t been able to use it with two devices at the same time. My model doesn’t have noise canceling but I’ve never really needed it.

7

I use the Trekz Air for the same purposes. They are bone conduction headphones, so you won’t get the powerful bass tones, but they sound good enough for me. I like that I can hear the traffic in addition to music when I ride my bicycle.

9

Depending on how loud the wind is, I may miss part of what is playing because my brain focuses on the louder noise. I am pretty happy with it.