Abstract: The kit for implanting a cementable endoprosthesis includes a fitting instrument and at least two components to be implanted, namely an endoprosthesis shaft and a proximal centering and/or sealing element, the shaft and the fitting instrument being designed to be able to be coupled to each other, and the centering and/or sealing element being designed to be placeable on the shaft and to be displaceable in the direction of extension of the latter, and either the fitting instrument including a limit stop part which forms a limit stop relative to the centering and/or sealing element, or a marking being arranged on the fitting instrument and on the shaft in order to ensure a defined mutual position between the centering and/or sealing element and the shaft.