The MP-412 REX is a Russian double-action .357 Magnum revolver with a break-action chamber and an automatic ejector. It was designed for export (REX, Revolver for EXport), but never put into full production due to lack of a market. The weapon was designed by IZHMECH, the state-owned Russian Izhevsk Mechanical Plant, which also designed and produced the Makarov PM semi-automatic pistol.