The QiYi/MFG 3×3 Core is the same core that comes with the QiYi/MFG 3×3 cubes, like the QiYi Sail 3×3, Thunderclap V1 and V2, and the Valk 3. It is compatible with the Valk 3 Hardware Set.
This core is a brand new core that is non-threaded. It is threaded by the screw when the screw is inserted.