LITTMANN® 3M CLASSIC II INFANT 2124 Ideal design, size and acoustic performance for use on newborns. We know you feel a special affection for infants. That's why you now have special 3M™ Littmann® Classic II Infant stethoscopes available to care for your little ones. The 3M™ Littmann® Classic II Infant stethoscope has been specially designed for use on the youngest patients. It provides high acoustic sensitivity, through the double-sided cone, for high and low frequency sounds. The Classic II Infant stethoscope is used by healthcare professionals and students to detect, listen to and study heart, lung and other body sounds for fitness assessment and diagnosis in infants.