3M Littmann Select Stethoscope. This Littmann Select stethoscope allows the user to listen selectively to low and high frequency without having to turn over the chest piece. The Select diaphragm is designed to pick up low frequency sounds, such as S3, S4 and those made by blood pressure, when using light pressure. The low profile chest piece fits comfortably under the cuff. 2 Year Warranty. Length: 28"/71 cm.