Littmann® Master Cardiology stethoscope with optional name engraving and carrying case Meets the expectations of healthcare professionals who require particularly high acoustic response. The 3M™ Littmann® Master Cardiology™ Cardiology Stethoscope features the best acoustic response in the Littmann line of mechanical stethoscopes. It features a tunable diaphragm, double barrel and an ergonomically designed precision stainless steel bell.