Abstract: The invention relates to a single-grip, rotational mixing faucet insertion piece developed as a control unit with ceramic insertion, which is connected in its one face to a base, on its other face to an operation arm. The control unit, the so-called cartridge comprises a fixed stationary inlet disc and an adjustable control disc placed one above the other forming thereby a plane seal. The other face of the inlet disc is connected to the base, whereas the side of the control disc opposite to the inlet disc is connected to the operating arm. The base contains an inlet for the hot water, and an inlet for the cold water and an outlet.