Photo-Me Model 9
circa 1946
The Model 9 and 11 looked very similar on the outside but there was a big difference on the inside! The Model 9 had complicated timer gears on the camera and only a single carrier allowing for only 1 photostrip to be developed at a time.
The Model 11 & 11A did away with alot of the giant mechanical gears using solenoids instead. The Spider was introduced allowing the machine to develop 7 sets of pictures.
Photo-Me Model 10
Photo-Me Model 11
commercial machine
circa 1955
While the Model 9 & 11 were for commercial use featuring a coin acceptor, the Model 10 and 11A were developed for businesses, specifically the Government & Military for ID purposes. The pictures were taken by a second person using an external button instead of coins and the subject had time to change positions for 4 different photos.
A couple of pictures of my Model 11.

You can see the top sign on my Model 14 in the background.