I have used one of these many times in my lifetime. They used to be against the clocking in machine in factories and shops. There are some of the original unused cards included.
 
These are great hung in the kitchen or hallway for the post that needs dealing with or with photos and cards displayed in them. An unusual place to store papers in a teenagers room and quirky too. They are easily wall hung.
 
This one is the IN card holder as it is clearly marked at the bottom.
 
Measurements: 85 x 11.3cm