Littmann Classic II S.E. Known as the standard in the industry, this performance stethoscope features the tunable diaphragm (Classic II S.E.) that allows both low and high frequency sound to be heard by simply alternating the pressure on the chest piece. The Classic II pediatric and infant stethoscopes feature the patented floating diaphragm technology. All models feature single-lumen tubing, nonchill rim, patented Littmann soft-sealing ear tips and three-year warranty. Classic II pediatric and infant style stethoscopes are optimally sized to facilitate sound sources in smaller patients. Teaching stethoscope model# 2138 includes two headsets.