Simply a large board supported more or less vertically( for example, a blackboard ) and covered with winceyette.
Other light items with winceyette attached can be stuck to the board very easily simply by pressing them against it, and will stay there until deliberately peeled off.
Our items are usually cards bearing text or pictures, and give no trouble. There's obviously a limit to the weight of the attached objects, but we've had no difficulties.
We used the board in ( at least ) one of our services :