Is there any Hearing Aid to use it on pool, ocean?

Nah! The bottom of the ocean is the best place for an apple watch or any other apple device I.M.H.O.

Waiting for the backlash

@SheikhD said:

Is there any hearing aid that may be a 100% waterproof to like go into the ocean, to do swimming or into a lake without getting the aids destroyed

Categorically and emphatically: NO.

That’s the short answer. Like you, finding a truly waterproof aid has been my quest for decades now, but the best that’s out there can barely survive a sweaty workout in the gym. Phonak actually got a lot of backlash several years ago for claiming their Lumity Life aids were WATERPROOF. They were supposed to survive submersion in up to 18” of water. So I put them to the test with a short swim in the pool where they were never below 6” in water. They DIED. They were under trial, so I got a replacement and never tried THAT again.

@storemanuk said:

Waiting for the backlash

Yep! You got my heart’s approval. I’ve got 2 feet and a couple of cinderblock EARS in the Android camp.