Could also connect a bunch of locks and put all the keys on a key ring. Lots of pictures of latch, lock, etc ideas for montessori type preschool. This lock one could be made with 2 boards, some o-rings, and some locks from Dollar Store.
Last Minute Latch Young House Love. Can't wait to make Jo her very own latch board! The kids at the library love ours and the homemade ones are so nice looking without the cheesy colors of storebought ones.