What is proposed is a closure unit consisting of a glass container (50) with external, circumferentially offset threaded elements (54, 55) on a container neck (52) of the glass container, and a closure cover made of sheet metal, wherein the closure cover (1, 2) has an encircling plastics layer (30; 30h, 30v) on the inside of the cover. The closure cover is pressed onto the container neck (52) and can be opened with a rotational movement via the threaded elements (54, 55) and a vertical section (30v) of the plastics layer. The container neck (52) has a horizontal end surface (52a) on which a horizontal section (30h) of the plastics layer rests under pressure in a sealing manner. A central region (11) of the closure cover passes with an adjoining, circumferentially oriented transition zone (11a, 11b, 11c) into an axially downwardly projecting skirt section (12) which ends in a roll-up region (21a, 21; 22). The plastics layer (30; 30h, 30v) is arranged on the inside of the cover in a manner adhering to the transition zone (11a, 11b, 11c) and the skirt section (12). An axial extent (h.sub.0) of the skirt section (12) and a radial dimension (b52) of the horizontally oriented end surface (52a) of the container neck (52) form a first ratio (v.sub.1) which is smaller than three.