Pokemon TCG: Hidden Fates Premium Powers Collection - Rules of Play says:

In the deep vastness where Legendary Pokémon roam, it is astonishingly rare to see even a single such legend—let alone three at once! This Premium Powers Collection combines the power of three cosmic Pokémon in one set of amazing etched foil cards that are sure to become the pride of your Pokémon TCG collection. Shiny Rayquaza-GX joins forces with special gold versions of Solgaleo-GX and Lunala-GX, and you'll even get a full-art oversize foil card of Shiny Rayquaza-GX. Add in a trove of Hidden Fates booster packs and a Pokémon TCG poster, and you have a set that both collectors and players will love!