OK, the watering can is a fountain, not a ring. Totally different scale. The ring shown in the other link is solid, probably resin, nothing (currently) wet.
The fountain has a glass or lucite tube and a pump. The water is pumped up in the clear pipe and overflows down the outside of the pipe so you can't really see that is solid, not just a stream of water. The faucet is separately attached and doesn't work -- just part of the illusion.
An acquarium pump, the tube, and some craftiness would probably be the key components to making these. They are a long-time magician's prop, so maybe you can find instructions if you look from that standpoint.