YGO 2019 Gold Sarcophagus Tin - Rules of Play says:
The 2019 Gold Sarcophagus Tin is fashioned after the iconic Gold Sarcophagus and is designed to reduce the amount of wear and tear sustained by the cards you keep in it, making it a stylish and efficient way to store cards that are important to you! Each tin will come with 5 Prismatic Secret Rare variant cards and 3 Mega-Packs of a specially crafted set featuring popular cards released in 2018 from booster sets Flames of Destruction, Dark Saviors, Cybernetic Horizon, and Soul Fusion.