3M Littmann Classic II Infant Stethoscope . Features: The 3M Littmann Classic II Infant Stethoscope snap-on rim will not rust nor corrode. Unlike threaded rims, it will not come loose nor fall off.• There is a crack-resistant, reinforced yoke that allows you to fold the scope easily into your pocket without kinking or breaking.• The internal double-leaf binaural spring helps assure a long life and allows easy adjustment of ear tube tension. The lightweight ear tubes are durable and abrasion-resistant.• Features a non-chill rim on both the diaphragm and bell, so there's no need to warm them up.