Took me a minute, too. I had to zoom in on it. It's a chalk holder and you can see the chalk at the top of each holder.
Oh, and I agree about the cameras. That film was for a 110 which was my first camera when I was 9 or 10. It took those bulbs in the pic for the flash, or we could get fancy with the flash bulb set that looked like a bar that had multiple ones so we didn't need to change to a new one with each pic.