The Sawyer's Pana-Vue Automatic R is a stack-loading viewer for 35mm slides. Easy to use: just slide the loader back and forth and the slides will drop onto the illuminated surface where you can then, err, view them. Another couple of slides back and forth and you're on the next slide. It's good times, unless the slides are of bad times, in which case it's bad times. Requires two C batteries (included)