The endless ribbon of glass is formed in the tin bath. Since glass is signifi-cantly lighter than tin, it flows or  loats on the molten tin – hence the Name “float glass”. The surface of the glass is thus absolutely planar. The thickness and width of the glass band are determined by top roller machines which grip into the soft glass ass at its edges. The balanced thickness of the glass ribbon is six millimetres. For thinner glass, the top rollers pull the glass outwards, for thicker glass they compress it inwards.