Here's how I use these in my zebra print 3rd grade classroom:
Print, laminate, cut. Then, attach a magnet to them. Each day, we start with all the letters in NOISE. During group work, if their noise level is too high, I remove a letter, beginning with the E at the end. I keep removing letters until all that's left is NO. At this time, the group work has now become independent work and there's no talking. Works like a charm!!
Would work in any grade level.