The invention relates to a seal lock (5) for spray plating an optimized metal and annular strip (1) in vacuum chambers, which is characterized in that metal rollers (10, 10', 11, 11';ellipsis) are arranged on brackets (30, 30',ellipsis) fixed on covers (6,7) and are not moveable like the brackets, and the axis of rollers of the same pair are arranged in the same vertical plane and the rollers areprovided with different diameters and the position of the rollers (10', 11',ellipsis) with a smaller diameter becomes higher or lower alternately when passing the given roller pair to the next pair, and the supporting brackets (40, 40'; 41,41';ellipsis) of the two rollers of the same pair are provided with transverse prominences (9, 9') which are towards the centre and are used to limit the secondgap corresponding to the basic gap of the rollers.