This file includes a 20 minute center rotation timer to use during center work. Includes five rotations worth of slides. Each slide counts down from twenty minutes, and includes center rules on the slide. At the beginning of the final three minutes of each rotation, chimes help signal the end of the center. The final slide is a three minute slide for each rotation includes directions for cleaning up and moving to the next center. In my classroom, I also add a three minute music clip to the final transition slide for each center as a auditory cue. Slides can be deleted or added for additional or less time.