Abstract: A device for applying by way of electrolysis a metal coat onto a cylinder-shaped body, especially for coppering a cylinder, with an outer tank and a process tank arranged above the outer tank, as well as with a circulation and filtering apparatus for the electrolyte. Two anode supports are installed in the process tank and connected to spray pipes. The supports are controlled by adjusting means arranged above the process tank. This latter is designed at its longitudinal ends with pockets whose inner walls are fitted with self-acting sealing elements for the projecting shaft ends of the cylinder.