The Vest Pocket cameras are very easily identified by the scissor mechanism that moves the front standard away from the body. For a long time I thought my Kodak Jiffy 620 was a Vest Pocket, and I thought the name derived from some strange source I didn't understand.
So I was very surprised when I finally acquired a proper Vest Pocket: it's a pixie! It won't literally fit in a vest pocket (not without a unsightly bulge), but it's obvious where the name comes from now. Even by modern standards it's small (it's not much bigger than my Elph); by early 20th Century standards it's tiny.
This guy takes 127 film (which you can still get from The Frugal Photographer), an obsolete film size that's better known as the film for the Baby Rolleiflex (but I have a couple others that take it too). And it's an autographic, which means you can pop the back open and write a message. Mine actually has the stylus still attached; very often they are missing.