The View-Master Model L was
produced from 1977 and was still being produced in 2000. Initially the
advance lever was a round ball, but that was modified to the disk design
shown below. During it's production run the company has changed names
four times, from GAF to VMI, to Ideal and finally to Tyco. This viewer
has been used as the basis for 'character' viewers, such as Batman,
Mickey Mouse, Big Bird and Casper.