YuXin Treasure Chest

The YuXin Treasure Chest is a 3x3 cube that has a hollowed core that can be used to store items, the core can only be accessed if you solve the cube (well technically only the white face) and push down on the white centre cap and then twist the white layer, despite it having a hollow core, it still turns surprisingly well, potentially better than some early speedcubes! It can even cornercut almost 45°!