'Visible' swiss watch

[5MUG]

Hi all. I have a watch which I think was my Grandmothers. It is gold (real) and has 'Visible' written on the face and 'Swiss' written at the bottom (below the numbers). it also has N written just to the left of the number 7 and M written just before the number 5.

Does anyone know anything about that make? I have goggled it but nothing appears. Thanks all, S