A suggestion box is a small covered box with an opening slit wide enough for an envelope or a folded piece of paper to be dropped in. It comes with a lock that secures the contents inside. It is commonly made of metal and wood. Usually labeled “suggestion box,” it is used for getting feedback, comments, and suggestions from people. It can be used in offices for employees to send in their suggestions, restaurants for getting comments from clients, or in seminars for getting opinions from the audience.