do they keep the water out totally...and do they stay in the ear while swimming?
RAMAZ K Yes to both questions. The trick to a good seal is the angle of insertion. It has to be inserted at almost 90 degrees upward (not sideways), which is a bit counterintuitive. Also, don't push them all the way in, but stop somewhere in the middle. I have been very happy with them, but it does take a couple of times of getting used to. They also sink, so avoid dropping them in the water.
MICHAEL B I have only used them a few times, but they did stay in and keep my years dry. I had to push them in a tiny bit farther than I would have liked so that the part that sticks out of your ear was not pressing against my swim cap, but not a big deal. I'd buy them again.
PHILIP L Sorry Joanne, never had a chance to try them
FRANCINE H I've used these on my last two snorkeling vacations in Hawaii. Before that I always got "swimmers ear". They stay in, keep water out (totally) and muffle but don't block hearing which is a safety plus.