The 3M Littmann Master Classic II Teaching Stethoscope features 3M's patented tunable diaphragm for improved low-frequency response and the ability to hear both low- and high-frequency sounds without turning over the chestpiece. Features a non-chill rim durable single-lumen tubing and solid stainless steel combination chestpiece. Two headsets allow instructor and student to perform auscultation on patients simultaneously.