The sound quality is quite good. The service is ok. There is a 2-year warranty. I used it twice within the two-year period because both of the ones I bought broke. In one case, there was no sound transfer in both earphones. In the second, they stopped working altogether. Now the third replacement has also broken. So, I would say the durability is not that great. I use them when I run (4 times/week, ~1+ hour) and when I swim (5-6 times/week, Apr-Nov, ~1+ hour). Conclusion: they are made to withstand reasonable use for a period of 2 years. Not more... Even so, they are better than others I have tried. So, it's up to each person to decide if they want to spend 150 euros to have waterproof earphones for 2 years.

It is the only Player that has survived in saltwater. I swim in the sea all year round and use them almost every day. I have bought almost all Players from China, after six months they all had problems from the salt. After about a year of almost daily use, they work fine. And in terms of quality, they are the best in Bone Conduction that I have used. I thought I should write this review to help people who use them in the sea because I have spent a lot of money on waterproof Mp3 Players from China that none of them survived in saltwater for more than 6 months.

They were purchased specifically for use in the pool.
Former owner of Sony, which really have an issue with their volume in water.
The shokz have excellent sound, they are very lightweight, they have very good button ergonomics, and you can check the battery status, play any folder you want separately or all together, and the songs can be played alphabetically or in random order.
Their construction seems sturdy, they have a two-year warranty, and I believe they are worth their money.
I tried them with and without earplugs, it's day and night without earplugs, the sound has a slight variation every time the ear canal fills and empties with water, so during swimming it becomes tiring because every time you turn your head to breathe, you hear a different sound, so in my opinion, ONLY with earplugs, the ones included in the package didn't work for me at all because they fell out of my ear and forced me to pull down my cap and cover my ear to prevent them from falling out, which resulted in pressure from the headphones on my head. With a pair of good earplugs (I have the ergo ones from arena), with the ears exposed, the cap not touching the ears, and the headphones at maximum volume, you can have a perfect training session in the pool, you get lost in the music and nothing else matters.
I really enjoyed this purchase, even though the price is a bit steep at €150, they are worth it... I would buy them again if something happens to them.

They were bought and are used for swimming in the sea.

Usage: for swimming in the sea, 1-4 hours every day for the past 3+ months.

Durability: 100% resistance to saltwater, at least when it comes to swimming - I don't dive.

Performance: quite strong intensity but not like in-ear headphones - good enough, I would say. They are quite good in terms of quality, especially if you want them for podcasts/audiobooks, etc. They have 2 modes, a regular one and a "swimming mode" which makes a big difference in the water.

Comfort: you forget you're wearing them! However, I don't use them with a swim cap, so I don't have an opinion on that. The fit is very good without putting pressure on the head.

Battery: lasts for 5+ hours. I haven't run out of battery yet. When you turn them on, it shows the battery status as low/medium/high. When I hear low or medium, I charge them. They charge very quickly - I think less than 2 hours. The battery is not replaceable.

Charger: be careful! The charger's "plug" is non-standard, which means that if it breaks, you can't simply use a USB-C/micro one, and it seems a bit fragile to me. That's why I take care of it like my eyes.

Connectivity: it's an MP3 player, not headphones. You put files from your computer into its built-in memory and it plays them. The computer sees it as a flash drive, FAT32 if I'm not mistaken - Linux compatible, so managing files is very easy. The only downside here is the very slow transfer speed, but if you're not in a hurry or if you have few files to transfer, it won't affect you.

Usability: it doesn't have a screen, only buttons. The only negative thing I found is that it doesn't have a fast-forward/backward function, so if you accidentally skip, you have to start the track from the beginning, which is particularly annoying for long files like 1hr+ audiobooks. I recommend breaking any large files into smaller parts (e.g. 10min parts) and maybe only filling it with what you intend to listen to during the day.

They can't be compared to in-ear headphones where everything gets waterlogged after a while and you have to put them on and take them off, and you don't have an extra waterproof case (MP3 player body) and cables to deal with.

Would I buy it again? Yes, again and again... yes!