Thanks! I had looked at this too as a backup, since i was looking at truly wireless and wasn't too sure where i can try it out to hear the audio quality.
Many brands claim "waterproof" and they showed them putting the buds in a cup. That's fine when the seals are new and fresh. Over time, the seal will corrode and potentially damage the devices. Such IP rating is good for accidental water issues or very short term underwater exposure, like taking brief photos.
In any case, Bluetooth does not work once it goes underwater. The signal instantly cuts off the moment your ears go underwater, then gets reconnected when you resurface, not usable at all. So even if these earbuds are "waterproof", you cannot listen to music when actually swimming.
Bragi The Dash has internal memory to playback audio, hence it is the only true wireless earbuds that you can continuously listen to music when swimming.
There are a handful of wireless waterproof earphones with built-in memory, not true wireless. Sony is one of the leaders in this category. I reviewed the WS623 and quite like it. Here is an excerpt of my thoughts which I published on my blog:
Looking at my previous review notes on the WS413, the WS623 appears to have improvements over the sound quality. Unlike the neutral tuning on the WS413, the WS623 sounds clear with sufficient details and brightness. The bass is firm and not boomy, certainly not going to please bassheads. When connecting over Bluetooth, there appears to be slight shift in the frequency response downwards. In Bluetooth mode, you can control the playback and volume with the respective buttons, as well as activating ambient mode.
And for the first time, I wore earphones for a swim, and I am loving it! Instead of hearing the swishing and swashing of waters against my ears, I get to enjoy uninterrupted music. Granted, the audio quality is not as clear due to the additional film on the swimming eartips, which makes the audio less bright.
The NW-WS623 puts some pressure against the ears to keep them from falling. As a result, it could cause discomfort to my ear canal bones after wearing for a while. Fortunately, the headset force enables me to place the earbuds just outside the ear canals loosely and continues to stay in place throughout my runs. The ambient mode does not create any excessive wind noise during runs, which is excellent.
Reference:
https://musicphotolife.com/2017/08/sony-nw-ws623-review-waterproof-dustproof-walkman-bluetooth/