PITTSBURGH, Pa., June 2008 left/RIGHT is the first ear muff designed so that the left muff differs from the right for better fit. These muffs are large enough to fit all ear types and sizes and are available in three noise reduction models: LOW (NRR 21), MEDIUM (NRR 25), and HIGH (NRR 28). Other features include new colors, new comfort headband design, and thin, flexible noise reduction rings.