As a syncronized swimmer, I have used almost all of the brands of noseplugs out there. These are the best that I have found. They stay on when your upside-down, jumping in and out of the water, and even usually stay on when i get hit in the face.
I've never had a problem with these, they keep the water out very well and stay on tight. If they are too tight or too lose, just bend it a little bit to fit. 5 stars

I used these nose clips when diving for sponges off the coast of Belize. I was able to wear them for over two hours without discomfort. Not a drop of water in my nose. My only complaint is that the color is unattractive. 4 stars

*****
I'm not a swimmer, but I use this nose clip to keep the air out of my nose so that I don't taste the oil I drink on a special diet I am on. I need to have a very tight seal or I will be able to taste the oil. I have experimented with several kinds of nose clips, and this one is absolutely the tightest seal. It is very strong, but not uncomfortable to wear. I'd thought a nose clip with a silicone pad would be more comfortable, but for me it's about the same, minus the tight seal of the Speedo. Although it is not as attractive as many of the other nose clips, I need effectiveness most of all, so I stick with Speedo.
***** 5 stars

I use a nose clip for swimming, and this one is the only that doesn`t came off in the first three or four strokes like the the other ones i`ve tried, unfortunately they don`t sell it in my country anymore, so i have to use amazon. 5 stars

For reasons that are obscure, a fair number of people lose weight if they use nose clips. No one is sure why, but for the people who are using SLD methods, including nose clips, this brand of nose clip is the nose clip of choice. So far there are about forty people experimenting with nose clips, and for what it is worth, they seem to be losing weight best with speedo.

I'm nonplussed by it, but if you are browsing around for SLD method weight loss and have come to this advertisement, you've found the nose clips on Amazon that everyone else bought. 5 stars