3D UK Quad from 1961 which has full instructions for the use of the “Special Viewer” This was doubly appropriate as the film involved the finding of a mask. Don’t you just love the instructions “Free viewer – without it you are just another mortal. With it you enter a weird new world and share the thrills and terror of Third Dimension!” “Important – When you enter the theatre you will be handed a special viewer. Each time the mask is used in the picture – look through the viewer for the shock of your life!” A cool cinema poster.