Pokémon Sun and Moon players who made the rankings in the tiny tourney Online Competition can now claim their participation prize – a special code that can be redeemed for Galladite, Gardevoirite and Lopunnite Mega Stones now through July 31, 2017, at 23:59 UTC. Just log in to the PGL using the game that you used to participate in the tiny tourney and click here. To redeem the code in your game, select Mystery Gift from the main menu, then select Receive Gift, and then select Get with Code/Password and follow the prompts to enter your special code. Be sure to enter the code in your copy of Pokémon Sun or Pokémon Moon before July 31, 2017, at 23:59 UTC. Visit the official Online Competitions page for tiny tourney Trainer and Pokémon rankings.
Source: Pokémon Global Link