I bought 4 of these and have used them twice so far. They have sort of worked, but they have issues.

These are not non-stick. The second time I used them I brushed the insides with oil. This did not seem to make much difference and still needed a spatula run around the inside to free the almost cooked eggs.

On both occasions there was egg white seeping out underneath the rings and into the pan. The pan is not warped and has a perfectly flat surface. Having the pan up to temperature before putting the eggs in did help a bit.

The yolk and top layer of the white does not cook. The eggs really need to be flipped, which is a skill that needs practice, as you have to do this with a half-cooked egg that is stuck to the ring. The egg needs to be removed from the ring before you can flip it because the handles prevent you from turning it over.

I tried to cover my pan with the lid to help cook/steam the top part of the egg, but the handles of the rings are a lot higher than the sides of my frying pan, so the lid couldn't be used.

On the bright side, I do get roundish eggs now. I just wish it was less of a hassle to do it.

They do work as long as you follow a few rules. First the pan needs to be hotter than normal & the rings need to be hot also. I found if you heat the pan up hotter than normal, then place the rings in the pan for a couple of minutes, when you drop your eggs in they form a seal by going white around the edges instantly so they don't leak under the edge, then you can lower your heat to normal to cook the egg. Also to cook the top you can either place a lid on your pan or since the rings are only silicon, chop the handles off so you can just flip the ring over. And lastly while the rings aren't non stick I found they don't hold by much anyway and can be released easily by running a bread knife around the inside.

They are really more of a hassle to use seeing as they don't do what they advertise. The egg would leak from the bottom of the pan and obviously it cannot be flipped. We tried to get them to suction attach to the bottom of the pan but that didn't really work either. They just sit in a drawer now. Would not buy again.