I don't understand the negative review that was left. When working professionally, it's the perfect ring. I bought several PK Ring by the past that are all in a closet. Other models are used for fun, video effects, and even Street Magic.
For professionals who want to use a PK effect at a time of their act, the Leo Smetsers's ring is perfect.
If I don't use the other rings it's because there is a risk that any metal object will "stick" to the ring, or that a spectator will trap me by touching or throwing a metal object on it. In addition, the other models are fragile in case of fall or shock.
As a professional, I 100% recommend Leo Smetsers's ring. We can activate on demand the "gimmick". I would have put the fifth star if it had been a little more raging, but because of its manufacture it makes sense.
Using a PK Ring for the cap in the bottle is not the best method for me.
If you want to do this, Axel Hecklau's method (ColaCap - Cap in bottle) is by far the absolute version you need. No ring is used, which makes the effect from the viewer's point of view totally impossible.
You understand, I recommend Neomagnetic Ring by Leo Smetsers.

There is nothing wrong with this ring as the other review has stated. (Depending on what level of magic your at). This is definately made for the professional magician who works. Yes there is a part that you canclearly see the ring ONLY if the ring is not on. If the ring ison the is a small silver outline however it is covered by your hand so no one ever sees it. and it can be deactivated so if anyone does suspect the ring which is a much higherlikeliness when working you can deactivate it and show its not magnetic at all. So its fantastic for the working magician. if its just for fun stick with the PK

Expensive...and weak ! I use PK rings a lot : cap in bottle, Spike trick, ...So I was teased by the advertising (of the kind that sells X-ray glasses to see the girls naked...). One hour after I received it, I sent it back to Penguin ! Keep your money for the original and best known one (G2, IMHO).