Z-Rings are unlocked at lvl70 together with Cross Server Gyms and Treasure Raid.
In this game mode you invest resources that you get from Cross Server Gyms and Treasure Raid in order to level up your Z-Rings.
Z-Rings can go up to lvl50. Once you reach lvl50, you can upgrade your Z-Ring into a Z-Bracelet which can go up to lvl100. A new Z-Ring is unlocked the moment your previous Z-Rings reaches lvl50.
Both Z-Rings and Z-Bracelets provide stats, but when a Z-Bracelet reaches lvl100 it will provide a special buff: 10% Skill Damage increase in specific types.
Here's a List of all Z-Bracelets and the types that receive this buff, once they reach lvl100:
- Mystery Bracelet - Normal / Fight
- Energy Bracelet - Psychic / Steel
- Miracle Bracelet - Water / Ice
- Crescent Bracelet - Grass / Dark
- Venom Bracelet - Poison / Ghost
- Fairy Bracalet - Fairy / Fire
- Flash Bracelet - Electric / Ground / Rock
- Blue Bracelet - Flying / Bug / Dragon
If you want to learn more about Z-Rings and Cross Server Gyms, check this video: