3M Littmann Master Cardiology Stethoscope, Smoke-Finish Chestpiece, Black Tube, 27 inch, 2176 Chestpiece delivers Littmanns highest acoustic performance along with handcrafted, eye-catching design Tunable diaphragm responds with a simple pressure change to capture low and high-frequency sounds Two-in-one tube design (dual lumen) eliminates noise interference from two external tubes rubbing together Special-Procedures Adaptor (included) for infant or pediatric auscultation adds versatility to the instrument Anatomically designed headset is angled to meet the path of the ear canal. Headset Material - Wide diameter aerospace alloy / Anodized aluminum. Diaphragm Material - Epoxy/Fiberglass