I use these letters with my 2nd grade students to monitor noise level in the classroom.
Using Velcro, I attached each letter to my whiteboard so they are visible to the entire class.
At the beginning of the year I explain to my students that each letter I have to pull down, because the noise has gotten too loud, will result in a whole class consequence. When I pull the N down, that is a warning to the class that it is getting too loud. I had my students decide on the consequences for the remaining letters. They came up with ideas such as no talking at all, 1 minute off of recess, I minute off of PE, etc.
At the end of the day, if all of the letters are still up, each student can pick between getting a skittle or a sticker. I also add 3 marbles to our "noise free" jar (when the jar is completely filled they get a special treat.)
My students absolutely love this classroom management technique, and I hope yours will too!