This is a reusable fastener. For temporarily holding paper documents, such as unpaid bills, lists, invitations, etc Print it, and mount it vertically. Place a marble in the cavity, the slope of the outer edge will hold the marble in place. To use it, push a piece of paper, up the slot, between the marble and the back wall. Gravity will keep the marble in place. The slope pushes the marble against the paper. Friction holds the paper in place. To release, pushe the marble up, and pull the paper down.