The Z-Ring is an all new item introduced in Generation VII. Alongside a Z-Crystal, it can trigger a Z-Move.
|| A mysterious ring that enables Pokémon to use Z-Power. It requires both the willpower and the physical power of the Trainer wearing it.
The Z-Ring is technically a white Mega Ring but instead of holding a Key Stone, it holds a Z-Crystal.
In the game the Z-Ring is first seen in its raw form as a Sparkling Stone. Then, given to the player character by Hala when he's done refining it after the player character has defeated Hau.
Ash, Kiawe, Lana, Lillie, Mallow, Sophocles, Gladion, Hau, Team Rocket, Hala, Olivia, Nanu, Hapu, Oluolu, Ida, Professor Kukui, Ilima, Pikala and Dia have Z-Rings.
The basic setup of a Z-Ring
A Toy Z-Ring and Pikachu from EB Games Australia
Ash, Sophocles, Kiawe, Mallow, Lillie and Lana with their Z-Rings
Team Rocket's Z-Power Ring